HighCVE-2026-39979

    jq: Out-of-Bounds Read in jv_parse_sized() Error Formatting for Non-NUL-Terminated Counted Buffers (CVE-2026-39979)

    Published Last modified Sources: Red Hat, SUSE, Debian LTS, Ubuntu, BSI, CVE.org, Msrc Update Guide

    What is affected, what to do

    jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jv_parse_sized() API in libjq accepts a counted buffer with an explicit length parameter, but its error-handling path formats the input buffer using %s in jv_string_fmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length.

    An exploit is publicly available. Update jqlang jq to version 2f09060afab23fe9390cce7cb860b10416e1bf5f.

    Affected
    • jqlang jq lt *..2f09060afab23fe9390cce7cb860b10416e1bf5f
    Fixed in
    • jqlang jq 2f09060afab23fe9390cce7cb860b10416e1bf5f

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    8.2

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    6.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: Red Hat, SUSE, Debian LTS, Ubuntu, BSI, CVE.org, Msrc Update Guide

    0.6 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 46.5

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    68.00 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    PoC (publicly reported)
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    8.2 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    6.5
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    6.9
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.6 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    46.5
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: proof of concept · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 14 April 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-125, CWE-125

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jv_parse_sized() API in libjq accepts a counted buffer with an explicit length parameter, but its error-handling path formats the input buffer using %s in jv_string_fmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length. This means that when malformed JSON is passed in a non-NUL-terminated buffer, the error construction logic performs an out-of-bounds read past the end of the buffer. The vulnerability is reachable by any libjq consumer calling jv_parse_sized() with untrusted input, and depending on memory layout, can result in memory disclosure or process termination. The issue has been patched in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f.

    Source: redhat_csaf, suse_csaf, Debian LTS Advisories, Ubuntu Security Notices, BSI WID Portal, BSI CSAF, NVD (NIST), Microsoft Security Update Guide, cvelistv5, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    jqlangjq
    • < 2f09060afab23fe9390cce7cb860b10416e1bf5f
    • < 1.8.2
    • 2f09060afab23fe9390cce7cb860b10416e1bf5f
    • 1.8.2
    redhatai_inference_server
    • 3.2.0 – < 3.2.2
    • 3.3.0 – < 3.3.5
    • 3.2.2
    • 3.3.5
    redhatansible_automation_platform
    • 2.0
    • —
    redhatceph_storage
    • 4.0
    • —
    redhatcodeready_linux_builder
    • 10.0
    • 9.0
    • 8.0
    • —
    • —
    • —
    redhatcodeready_linux_builder_eus
    • 10.0
    • 9.6
    • 9.4
    • —
    • —
    • —
    redhathardened_images
    • —
    • —
    redhatopenshift_ai
    • 3.4 – < 3.4.3
    • 3.4.3
    redhatopenshift_container_platform
    • 4.15 – < 4.15.65
    • 4.14 – < 4.14.68
    • 4.12 – < 4.12.92
    • 4.13 – < 4.13.68
    • 4.19 – < 4.19.33
    • 4.18 – < 4.18.44
    • 4.16 – < 4.16.64
    • 4.17 – < 4.17.55
    • 4.15.65
    • 4.14.68
    • 4.12.92
    • 4.13.68
    • 4.19.33
    • 4.18.44
    • 4.16.64
    • 4.17.55
    Red HatEnterprise Linux
    • Hardened Images RPMs jq
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxredhatenterprise_linux10.0
    Linuxredhatenterprise_linux8.0
    Linuxredhatenterprise_linux9.0
    Linuxredhatenterprise_linux_aus8.4
    Linuxredhatenterprise_linux_aus8.6
    Linuxredhatenterprise_linux_eus10.0
    Linuxredhatenterprise_linux_eus8.4
    Linuxredhatenterprise_linux_eus9.4
    Linuxredhatenterprise_linux_eus9.6
    Linuxredhatenterprise_linux_tus8.6
    Linuxredhatenterprise_linux_tus8.8
    Linuxredhatenterprise_linux_update_services_for_sap_solutions8.6
    Linuxredhatenterprise_linux_update_services_for_sap_solutions8.8
    Linuxredhatenterprise_linux_update_services_for_sap_solutions9.0
    Linuxredhatenterprise_linux_update_services_for_sap_solutions9.2
    Linuxdebianjqbookworm
    Linuxdebianjqbullseye

    Weakness classes (CWE)

    • CWE-125Out-of-bounds Read

      Base

      The product reads data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-125

    • CWE-125Out-of-bounds Read

      Base

      The product reads data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-125

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    References & sources

    • github.comjqlang/jq/security/advisories/GHSA-2hhh-px8h-355px_refsource_CONFIRM, Exploit, Vendor advisory
    • github.comjqlang/jq/commit/2f09060afab23fe9390cce7cb860b10416e1bf5fx_refsource_MISC, Patch
    • access.redhat.comsecurity/cve/CVE-2026-39979Vulnerability database, x_refsource_REDHAT, Third-party advisory
    • bugzilla.redhat.comRHBZ#2458077Issue tracking, x_refsource_REDHAT, Issue tracking, Third-party advisory
    • security.access.redhat.comdata/csaf/v2/vex/2026/cve-2026-39979.jsonx_sadp-csaf-vex, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:26528Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:26542Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:28887Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:23233Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:25044Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:34098Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:25181Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:23245Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:16252Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:18048Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:18047Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:18046Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:18045Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:18044Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comerrata/RHSA-2026:18040Vendor advisory, x_refsource_REDHAT, Third-party advisory

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. NVD analysis modifiedNVD

      Product mapping changed:
      Show 32 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Product configurationadded
      —
      OR *cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:ceph_storage:4.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_aus:8.4:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:* *cpe:2.3:a:redhat:codeready_linux_builder:8.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_tus:8.6:*:*:*:*:*:*:* *cpe:2.3:a:redhat:ansible_automation_platform:2.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_aus:8.6:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_tus:8.8:*:*:*:*:*:*:* *cpe:2.3:a:redhat:codeready_linux_builder:9.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.8:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:9.2:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:9.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:9.4:*:*:*:*:*:*:* *cpe:2.3:a:redhat:codeready_linux_builder_eus:9.4:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:9.6:*:*:*:*:*:*:* *cpe:2.3:a:redhat:codeready_linux_builder:10.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:10.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:codeready_linux_builder_eus:9.6:*:*:*:*:*:*:* *cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:* *cpe:2.3:a:redhat:ai_inference_server:*:*:*:*:*:*:*:* versions from (including) 3.3.0 up to (excluding) 3.3.5 *cpe:2.3:a:redhat:codeready_linux_builder_eus:10.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:ai_inference_server:*:*:*:*:*:*:*:* versions from (including) 3.2.0 up to (excluding) 3.2.2 *cpe:2.3:a:redhat:openshift_ai:*:*:*:*:*:*:*:* versions from (including) 3.4 up to (excluding) 3.4.3 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.13 up to (excluding) 4.13.68 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.14 up to (excluding) 4.14.68 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.15 up to (excluding) 4.15.65 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.16 up to (excluding) 4.16.64 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.17 up to (excluding) 4.17.55 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.18 up to (excluding) 4.18.44 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.19 up to (excluding) 4.19.33 *cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:* versions from (including) 4.12 up to (excluding) 4.12.92
      Product configurationchanged
      OR *cpe:2.3:a:jqlang:jq:*:*:*:*:*:*:*:* versions up to (excluding) 2026-04-12
      OR *cpe:2.3:a:jqlang:jq:*:*:*:*:*:*:*:* versions up to (excluding) 1.8.2
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:16252 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:16692 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:16693 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18040 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18042 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18043 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18044 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18045 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18046 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18047 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:18048 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:19151 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:19365 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:23233 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:23245 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:25044 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:25096 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:25181 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:26528 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:26542 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:28887 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30078 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30087 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30088 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30089 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:34098 Types: Third Party Advisory
      Reference typeadded
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      redhat-SADP: https://access.redhat.com/errata/RHSA-2026:8579 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://access.redhat.com/security/cve/CVE-2026-39979 Types: Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://bugzilla.redhat.com/show_bug.cgi?id=2458077 Types: Issue Tracking, Third Party Advisory
      Reference typeadded
      —
      redhat-SADP: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39979.json Types: Third Party Advisory

      Source identifier: nvd@nist.gov

    One NVD translation into another language is hidden.

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    <a href="https://intel.neosec.eu/en/cve/CVE-2026-39979"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-39979.svg?lang=en" alt="CVE-2026-39979 – NEOSEC Intel" height="20"></a>