CriticalCVE-2026-97205

    NGINX ngx_http_core_module vulnerability (CVE-2026-97205)

    Published Last modified Sources: Debian, OSV, Msrc Update Guide, CVE.org, F5, BSI

    What is affected, what to do

    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module. When asynchronous file I/O (AIO) is enabled in certain configurations, processing a Server Side Includes (SSI) page containing “include virtual” commands may trigger a Use-After-Free (UAF) in the NGINX worker process.

    Update F5 NGINX Open Source to version 1.31.7, F5 NGINX Open Source to version 1.30.6, F5 NGINX Plus to version 37.1.0.1.

    Affected
    • F5 NGINX Plus gte R35..*
    • F5 NGINX Plus gte R34..*
    • F5 NGINX Plus gte R33..*
    • F5 NGINX Open Source lt 1.31.0..1.31.7
    • F5 NGINX Open Source lt 1.30.0..1.30.6
    • F5 NGINX Plus lt 37.1.0..37.1.0.1
    • F5 NGINX Plus lt 37.0.0..37.0.5.1
    • F5 NGINX Plus gte R36..*
    Fixed in
    • F5 NGINX Open Source 1.31.7
    • F5 NGINX Open Source 1.30.6
    • F5 NGINX Plus 37.1.0.1
    • F5 NGINX Plus 37.0.5.1

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

    Metrics

    9.2

    Priority

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

    Source: Vendor (CNA), CVSS v4

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Debian, OSV, Msrc Update Guide, CVE.org, F5, BSI

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 40.4

    Show all metrics
    Severity
    Critical
    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
    89.08 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
    9.2 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
    8.1
    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
    9.2
    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
    0.5 %
    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
    40.4
    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
    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-416

    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

    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module. When asynchronous file I/O (AIO) is enabled in certain configurations, processing a Server Side Includes (SSI) page containing “include virtual” commands may trigger a Use-After-Free (UAF) in the NGINX worker process. This may cause memory corruption or a worker process crash. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system, corrupt its memory, or possibly trigger code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

    Source: Debian Security Advisories, OSV (Open Source Vulnerabilities), Microsoft Security Update Guide, cvelistv5, NVD (NIST), f5_askf5, BSI WID Portal, BSI CSAF

    Affected products

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

    Affected products
    VendorProductAffected versionsFixed in
    F5NGINX Open Source
    • 1.30.0 – < 1.30.6
    • 1.31.0 – < 1.31.7
    • 1.30.6
    • 1.31.7
    F5NGINX Plus
    • ≥ R36
    • 37.0.0 – < 37.0.5.1
    • ≥ R35
    • 37.1.0 – < 37.1.0.1
    • ≥ R33
    • ≥ R34
    • —
    • 37.0.5.1
    • —
    • 37.1.0.1
    • —
    • —
    NGINXNGINX
    • NGINX App Protect DoS
    • App Protect WAF
    • —
    • —
    NGINXNGINX F5 DoS
    • < 4.11.0
    • 4.11.0
    NGINXNGINX F5 WAF
    • < 5.14.2
    • < 5.16.0
    • 5.14.2
    • 5.16.0
    NGINXNGINX Gateway Fabric
    • < 2.8.0
    • 2.8.0
    NGINXNGINX Ingress Controller
    • < 5.7.0
    • 5.7.0
    NGINXNGINX Instance Manager
    • < 2.24.0
    • 2.24.0
    NGINXNGINX JavaScript (njs)
    • < 1.0.2
    • 1.0.2
    NGINXNGINX Open Source
    • < 1.31.7
    • < 1.30.6
    • 1.31.7
    • 1.30.6
    NGINXNGINX Plus
    • < 37.0.5.1
    • < 37.0.7.1
    • < 37.2.0.1
    • < 37.1.0.1
    • 37.0.5.1
    • 37.0.7.1
    • 37.2.0.1
    • 37.1.0.1
    Distribution and container packages (4)

    Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.

    Distribution and container packages
    VendorProductAffected versionsFixed in
    bitnaminginx
    • 1.30.0
    • 1.31.0
    • 1.30.6
    • 1.31.7
    bitnaminginx-gateway
    • 1.31.0
    • 1.30.0
    • 1.31.7
    • 1.30.6

    Affected operating systems

    Affected operating systems
    FamilyVendorProductVersion
    Linuxdebiannginxtrixie

    Weakness classes (CWE)

    • CWE-416Use After Free

      Variant

      The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

      Entry at MITRE CWE-416

    References & sources

    • my.f5.commanage/s/article/K000162608Vendor advisory, web
    • NVD (NIST)vuln/detail/CVE-2026-97205web

    Reanalysis & status changes

    Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

    1. CVE Modified134c704f-9b21-4f2e-91b3-4a467353bcc0

      • SSVC: before {"id":"CVE-2026-97205","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…
      • SSVC: after {"id":"CVE-2026-97205","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…

    2. CVE Modified134c704f-9b21-4f2e-91b3-4a467353bcc0

      • SSVC: after {"id":"CVE-2026-97205","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…

    3. New CVE Receivedf5sirt@f5.com

      • Description: after NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module. When asynchronous file I/O (AIO) is enabled in certain configurations, processing a Server Side Includes (SSI) page containing “include virtual” commands may trigger a Use-After-Free (UAF) in the NGINX worker process. This may cause memory corruption or a worker process crash. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system, corrupt its memory, or possibly trigger code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
      • CVSS V4.0: after AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      • CVSS V3.1: after AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
      • CWE: after CWE-416

    Linked advisories

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2026-97205
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-97205"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-97205.svg?lang=en" alt="CVE-2026-97205 – NEOSEC Intel" height="20"></a>