CVEs / CVE-2026-111497
CVE-2026-111497: Google Brotli Unchecked Return Value Vulnerability
- Known exploited in the CISA KEV catalog since 27 Oct 2026
- critical 9.8 CVSS 3.1 (NVD)
- EPSS 82.6% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Google Brotli contains an unchecked return value vulnerability that 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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Google Brotli | from 1.0.3, before 1.0.10 | 1.0.10 |
| Google Brotli | from 1.1.0, before 1.1.1 | 1.1.1 |
| Google Brotli | from 1.2.0, before 1.2.1 | 1.2.1 |
| Siemens Cloud Connector Configurator | all versions | — |
| Siemens Common Configurator (CC on IEM) | all versions | — |
| Siemens Common Configurator on Device (CC on Edge) | all versions | — |
| Siemens Data Flow Monitoring | all versions | — |
| Siemens Databus Configurator | all versions | — |
| Siemens Edge OPC UA Server Configurator | all versions | — |
| Siemens Flow Creator Configurator | all versions | — |
| Siemens Industrial Edge Hub | all versions | — |
| Siemens Industrial Edge Management Cloud | all versions | — |
| Siemens RUGGEDCOM APE1808 | all versions | — |
| Product | Affected | Fixed in |
|---|---|---|
| brotli (PyPI) | from 1.0.3, before 1.2.1 | 1.2.1 |
| brotlicffi (PyPI) | from 1.0.3, before 1.2.1.0 | 1.2.1.0 |
Package versions from GHSA-9v8h-qqgm-4m35.
Exploitation
| In CISA KEV since | 27 Oct 2026 |
|---|---|
| Due date for US federal agencies | 10 Nov 2026 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-252, CWE-787 |
On the Stackurity blog
- Ubuntu USN-8958-1 fixes three .NET flaws, one exploited 30 Oct 2026
- CISA adds Adobe Commerce and Magento flaw CVE-2026-48356 to exploited list 29 Oct 2026
- CISA adds two PHP remote code execution flaws to its KEV list 28 Oct 2026
- Brotli CVE-2026-111497: exploited decoder flaw, how to fix it 28 Oct 2026
References
- CVE-2026-111497 on NVD
- CVE-2026-111497 in the CISA KEV catalog
- https://github.com/google/brotli/releases/tag/v1.2.1 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- CVE-2026-111497 on OSV
- https://github.com/andybalholm/brotli/releases/tag/v1.2.7 Release Notes
- 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 Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/10/23/25 Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/10/24/6 Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/10/26/12 Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/10/26/13 Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/10/26/16 Mailing List, Third Party Advisory
- https://broccoli2shell.com Third Party Advisory
- https://github.com/advisories/GHSA-9v8h-qqgm-4m35 Third Party Advisory
- https://github.com/dotnet/announcements/issues/494 Issue Tracking, Mitigation, Third Party Advisory
- https://github.com/google/brotli/releases/tag/v1.0.10 Release Notes
- https://github.com/google/brotli/releases/tag/v1.1.1 Release Notes
- https://github.com/google/brotli/releases/tag/v1.2.1 Release Notes
- https://lists.debian.org/debian-lts-announce/2026/10/msg00049.html Mailing List, Third Party Advisory
- https://patchtheplanet.org/brotli Third Party Advisory
- https://www.aikido.dev/blog/node2shell-nodejs-brotli-rce-cve-2026-111497 Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-045512.html Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-443410.html Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-898633.html Third Party Advisory
- https://ellio.tech/en/blog/node2shell-cve-2026-111497-rce-on-stock-nodejs-builds/ Third Party Advisory
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.