Libxml2: memory leak leading to local denial of service in xmllint interactive shell (CVE-2026-1757)
Published Last modified Sources: Red Hat, Debian LTS, Ubuntu, CVE.org
What is affected, what to do
A flaw was identified in the interactive shell of the xmllint utility, part of the libxml2 project, where memory allocated for user input is not properly released under certain conditions. When a user submits input consisting only of whitespace, the program skips command execution but fails to free the allocated buffer.
Update Red Hat Hardened Images to version 2.15.2-0.3.hum1.
- Affected
- Red Hat Hardened Images
lt *..2.15.2-0.3.hum1
- Red Hat Hardened Images
- Fixed in
- Red Hat Hardened Images
2.15.2-0.3.hum1
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Metrics
6.2
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
6.2
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: Red Hat, Debian LTS, Ubuntu, CVE.org
0.2 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 12.2
Show all metrics
- Severity
- Medium
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- 46.10 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- no public PoC known
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- 6.2 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- 6.2
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- 0.2 %
- 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- 12.2
- Elevated — this CVE ranks above at least 10% of all CVEs scored today.
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: none known · not automatable · Technical impact: partial
- Source: CISA Vulnrichment, as of 2 February 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-401
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- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
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
A flaw was identified in the interactive shell of the xmllint utility, part of the libxml2 project, where memory allocated for user input is not properly released under certain conditions. When a user submits input consisting only of whitespace, the program skips command execution but fails to free the allocated buffer. Repeating this action causes memory to continuously accumulate. Over time, this can exhaust system memory and terminate the xmllint process, creating a denial-of-service condition on the local system.
Source: redhat_csaf, Debian LTS Advisories, Ubuntu Security Notices, cvelistv5, NVD (NIST), CVE.org (MITRE)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 |
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| Red Hat | Red Hat Enterprise Linux 6 |
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| Red Hat | Red Hat Enterprise Linux 7 |
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| Red Hat | Red Hat Enterprise Linux 8 |
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| Red Hat | Red Hat Enterprise Linux 9 |
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| Red Hat | Red Hat Hardened Images |
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| Red Hat | Red Hat JBoss Core Services |
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| Red Hat | Red Hat OpenShift Container Platform 4 |
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Vendors and products
- Debian Libxml2
- Red Hat Red Hat Enterprise Linux 10
- Red Hat Red Hat Enterprise Linux 6
- Red Hat Red Hat Enterprise Linux 7
- Red Hat Red Hat Enterprise Linux 8
- Red Hat Red Hat Enterprise Linux 9
- Red Hat Red Hat Hardened Images
- Red Hat Red Hat Jboss Core Services
- Red Hat Red Hat Openshift Container Platform 4
- Ubuntu Libxml2
Affected operating systems
| Linux | debian | libxml2 | bullseye |
| Linux | ubuntu | libxml2 | questing |
| Linux | ubuntu | libxml2 | resolute |
Weakness classes (CWE)
CWE-401Missing Release of Memory after Effective Lifetime
Variant
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Entry at MITRE CWE-401
References & sources
- access.redhat.comRHSA-2026:7519Vendor advisory, x_refsource_REDHAT
- access.redhat.comsecurity/cve/CVE-2026-1757Vulnerability database, x_refsource_REDHAT
- bugzilla.redhat.comRHBZ#2435940Issue tracking, x_refsource_REDHAT
- gitlab.gnome.orgGNOME/libxml2/-/issues/1009
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).
Record modifiedRed Hat
Show 9 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/1xxx/CVE-2026-1757.json">CVE-2026-1757</a>Reference added —https://access.redhat.com/errata/RHSA-2026:7519Reference added —https://access.redhat.com/security/cve/CVE-2026-1757Reference added —https://bugzilla.redhat.com/show_bug.cgi?id=2435940Reference added —https://gitlab.gnome.org/GNOME/libxml2/-/issues/1009Reference removed https://access.redhat.com/errata/RHSA-2026:7519—Reference removed https://access.redhat.com/security/cve/CVE-2026-1757—Reference removed https://bugzilla.redhat.com/show_bug.cgi?id=2435940—Reference removed https://gitlab.gnome.org/GNOME/libxml2/-/issues/1009—Source identifier: secalert@redhat.com
Record modifiedRed Hat
1 individual change: Affected versions (publisher)
Show the original change
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) changed Red Hat Hardened Images, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 (+5)Red Hat Hardened Images, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 (+5)Source identifier: secalert@redhat.com
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-1757"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-1757.svg?lang=en" alt="CVE-2026-1757 – NEOSEC Intel" height="20"></a>