CriticalCVE-2026-111497

    Out-of-Bounds Write in Google Brotli Decoder (CVE-2026-111497)

    Published Last modified Sources: Fortinet PSIRT, CVE.org, pwn.watch, Msrc Update Guide, SingCERT, Palo Alto Networks, Ubuntu, HKCERT, OSV, Debian LTS, Red Hat, Debian, BSI

    What is affected, what to do

    A buffer overflow vulnerability in the Brotli decoder (c/dec/decode.c) in Google Brotli versions 1.0.3 through 1.2.0 on all platforms allows a remote unauthenticated attacker to corrupt adjacent decoder state memory, disclose sensitive memory contents, cause a denial of service, or potentially execute arbitrary code using a crafted Brotli-compressed stream. Users need to update any Brotli libraries or binaries between 1.0.3 through 1.2.0 to the latest available version: 1.0.10 or 1.1.1 or 1.2.1.

    The vulnerability is being actively exploited; treat it as a priority. Update Google Brotli to version 1.0.10, Google Brotli to version 1.1.1, Google Brotli to version 1.2.1.

    Affected
    • Google Brotli lt 1.0.3..1.0.10
    • Google Brotli lt 1.1.0..1.1.1
    • Google Brotli lt 1.2.0..1.2.1
    Fixed in
    • Google Brotli 1.0.10
    • Google Brotli 1.1.1
    • Google Brotli 1.2.1

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

    Metrics

    9.8

    Priority

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

    Source: Vendor (CNA), CVSS v3

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Fortinet PSIRT, CVE.org, pwn.watch, Msrc Update Guide, SingCERT, Palo Alto Networks, Ubuntu, HKCERT, OSV, Debian LTS, Red Hat, Debian, BSI

    36.0 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 98.5

    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
    153.55 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
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    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
    9.8 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
    36.0 %
    Elevated — model estimates 10-50% 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
    98.5
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    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-787, CWE-252

    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
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    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
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    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 buffer overflow vulnerability in the Brotli decoder (c/dec/decode.c) in Google Brotli versions 1.0.3 through 1.2.0 on all platforms allows a remote unauthenticated attacker to corrupt adjacent decoder state memory, disclose sensitive memory contents, cause a denial of service, or potentially execute arbitrary code using a crafted Brotli-compressed stream. Users need to update any Brotli libraries or binaries between 1.0.3 through 1.2.0 to the latest available version: 1.0.10 or 1.1.1 or 1.2.1.

    Source: fortinet_rss, cvelistv5, pwn.watch, NVD (NIST), Microsoft Security Update Guide, CSA/SingCERT, paloalto_rss, Ubuntu Security Notices, HKCERT (CC BY 3.0 HK) · HKCERT rating: high, OSV (Open Source Vulnerabilities), Debian LTS Advisories, redhat_csaf, Debian Security Advisories, 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
    Affected versionsFixed in
    GoogleBrotli
    • 1.1.0 – < 1.1.1
    • 1.2.0 – < 1.2.1
    • 1.0.3 – < 1.0.10
    • 1.1.1
    • 1.2.1
    • 1.0.10
    Open SourceNode.js
    • < 22.23.4
    • < 26.12.1
    • < 24.22.1
    • 22.23.4
    • 26.12.1
    • 24.22.1
    pypibrotli
    • 0.5.2
    • 1.0.8
    • 0.6.0
    • 1.0.4
    • 1.2.0
    • 1.0.1
    • 1.1.0
    • 1.0.7
    • 1.0.9
    • 1.0.3
    • 1.0.6
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • 1.2.1
    • —
    • 1.2.1
    pypibrotlicffi
    • 1.1.0.0
    • 1.0.3
    • 1.2.0.2
    • —
    • 1.2.0.0
    • 1.0.9.1
    • 1.2.0.1
    • 0.8.0
    • 1.0.9.0
    • 1.0.9.2
    • —
    • 1.2.1.0
    • —
    • 1.2.1.0
    • —
    • —
    • —
    • —
    • —
    • —
    Distribution and container packages (6)

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

    Distribution and container packages
    Affected versionsFixed in
    bitnaminode
    • —
    • 23.0.0
    • 26.0.0
    • 22.23.4
    • 24.22.1
    • 26.12.1
    bitnaminode-min
    • —
    • 23.0.0
    • 26.0.0
    • 22.23.4
    • 24.22.1
    • 26.12.1

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianbrotlibookworm
    Linuxdebianbrotlitrixie
    Linuxubuntubrotlijammy
    Linuxubuntubrotlinoble
    Linuxubuntubrotliresolute
    Linuxubuntubrotlistonking

    Weakness classes (CWE)

    • CWE-787Out-of-bounds Write

      Base

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

      Entry at MITRE CWE-787

    • CWE-252Unchecked Return Value

      Base

      The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions.

      Entry at MITRE CWE-252

    References & sources

    • nodejs.orgen/blog/vulnerability/october-2026-security-releasesPatch, web
    • NVD (NIST)CVE-2026-111497 (NVD)web, pwn-watch, advisory
    • imperva.comNode2Shell: From Brotli Data to Remote Code ExecutionExploit, pwn-watch
    • GitHub Security Advisoriesadvisories/GHSA-9v8h-qqgm-4m35
    • openwall.comlists/oss-security/2026/10/23/25
    • lists.debian.orgdebian-lts-announce/2026/10/msg00049.html
    • pwn.watchpwn.watch: Node2Shell / HTTP2Shell: Brotli RCE (CVE-2026-111497) in Node.js, Python, Envoy and Istio + Node.js October releasespwn-watch
    • opensourcemalware.comPython Packages Vulnerable to Node2Shellpwn-watch, web
    • thehackernews.comResearchers Demonstrate Node2Shell RCE Exploit on Node.js Build Using Crafted Brotli Datapwn-watch
    • nodejs.orgWednesday, October 21, 2026 Security Releasespwn-watch, web
    • nodejs.orgNode.js 26.12.1 (Current)pwn-watch
    • vercel.comVercel bulletin: Brotli decoder RCEpwn-watch
    • aikido.devNode2Shell: Node.js Brotli vulnerability allows remote code execution (CVE-2026-111497)pwn-watch
    • github.comOut-of-Bounds Write in Brotli Decompressor (GHSA-3wvj-j6qm-62mr)pwn-watch
    • patchtheplanet.orgBrotli vulnerability (CVE-2026-111497)pwn-watch
    • aikido.devNode2Shell evolves to HTTP2Shell. Brotli flaw (CVE-2026-111497) blast radius affects many libraries & apps using HTTPs.pwn-watch
    • news.ycombinator.comEvolving Threat: http2shell is an RCE in node, Python, and more (discussion)pwn-watch
    • github.comgoogle/brotli/commit/0ed4268a4401abcb4472096340477cf4af7d1a2bweb, fix
    • github.comgoogle/brotli/commit/50a9b70a4d5e1443fc40927952276b68fffa83a0web
    • github.comgoogle/brotli/commit/b418fa81c48262a86a95332b0bc6d62c30aa78b6web

    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. Record modifiedgoogle.com

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/andybalholm/brotli/releases/tag/v1.2.7

      Source identifier: cve-coordination@google.com

    2. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/10/26/16

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    3. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://patchtheplanet.org/brotli

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    4. Record modifiedCVE Program

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://broccoli2shell.com
      Referenceadded
      —
      https://github.com/dotnet/announcements/issues/494
      Referenceadded
      —
      https://github.com/google/brotli/releases/tag/v1.0.10
      Referenceadded
      —
      https://github.com/google/brotli/releases/tag/v1.1.1
      Referenceadded
      —
      https://github.com/google/brotli/releases/tag/v1.2.1
      Referenceadded
      —
      https://www.aikido.dev/blog/node2shell-nodejs-brotli-rce-cve-2026-111497

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    5. Record modifiedCVE Program

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/10/26/12
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/10/26/13

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    Show 8 older changes

    1. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/10/24/6

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentremoved
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-23T13:25:59.976575Z"}
      —
      SSVC assessmentadded
      —
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-23T00:00:00+00:00"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    3. Record modifiedCVE Program

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/10/23/25
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2026/10/msg00049.html

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    4. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/advisories/GHSA-9v8h-qqgm-4m35

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    5. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceremoved
      https://www.imperva.com/blog/node2shell-from-brotli-data-to-remote-code-execution/
      —
      SSVC assessmentremoved
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-23T12:56:59.549410Z"}
      —
      SSVC assessmentadded
      —
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-23T13:25:59.976575Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    6. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: proof of concept, automatable: no

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://www.imperva.com/blog/node2shell-from-brotli-data-to-remote-code-execution/
      SSVC assessmentremoved
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-22T14:15:10.861688Z"}
      —
      SSVC assessmentadded
      —
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-23T12:56:59.549410Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    7. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-111497","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-22T14:15:10.861688Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    8. Receivedgoogle.com

      CVSS V4.0: AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

      Weakness type: CWE-787, CWE-252

      Description added or changed

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      A buffer overflow vulnerability in the Brotli decoder (c/dec/decode.c) in Google Brotli versions 1.0.3 through 1.2.0 on all platforms allows a remote unauthenticated attacker to corrupt adjacent decoder state memory, disclose sensitive memory contents, cause a denial of service, or potentially execute arbitrary code using a crafted Brotli-compressed stream. Users need to update any Brotli libraries or binaries between 1.0.3 through 1.2.0 to the latest available version: 1.0.10 or 1.1.1 or 1.2.1.
      CVSSadded
      —
      AV:N/AC:L/AT:P/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
      Weakness type (CWE)added
      —
      CWE-787
      Weakness type (CWE)added
      —
      CWE-252
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/111xxx/CVE-2026-111497.json">CVE-2026-111497</a>
      Referenceadded
      —
      https://nodejs.org/en/blog/vulnerability/october-2026-security-releases#nodejs-brotli-decoder-out-of-bounds-write-permits-remote-code-execution-cve-2026-111497---high

      Source identifier: cve-coordination@google.com

    Linked advisories

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    <a href="https://intel.neosec.eu/en/cve/CVE-2026-111497"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-111497.svg?lang=en" alt="CVE-2026-111497 – NEOSEC Intel" height="20"></a>