Vulnerability-Lookup

PYSEC-2026-4322

Vulnerability from pysec - Published: 2026-10-23 00:00 - Updated: 2026-10-23 00:00

Details

CVE-2026-111497 ("Node2Shell") is an out-of-bounds write (CWE-787) in Google's Brotli decoder (c/dec/decode.c). DecodeBlockTypeAndLength() returns an ambiguous value for an invalid block switch, and the fast decode path discards it (CWE-252, unchecked return value), so a crafted Brotli stream makes the decoder continue on corrupted state and write past the ring buffer. Upstream rates it CVSS 4.0 9.2 and classifies the impact as potential remote code execution.

The vulnerability is in Google's C library, not in Node.js specifically. The PyPI Brotli package is Google's CPython binding and compiles the same c/dec/decode.c that has the actual vulnerability. All Brotli releases up to and including 1.2.0 ship the vulnerable decoder; 1.2.1 contains the upstream fix (commit 0ed4268a) and differs from 1.2.0 only in that fix plus a version bump.

The decoder is reached whenever untrusted Brotli data is decompressed. With Brotli installed, common HTTP clients decode Brotli responses automatically (urllib3/requests, httpx with the brotli extra, aiohttp) and services that accept Content-Encoding: br request bodies decode inbound data, so the flaw is reachable from attacker-controlled input.

Severity

9.2 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Impacted products

Name	purl
brotli	pkg:pypi/brotli

Aliases

CVE-2026-111497

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "brotli",
        "purl": "pkg:pypi/brotli"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.5.2",
        "0.6.0",
        "1.0.1",
        "1.0.4",
        "1.0.6",
        "1.0.7",
        "1.0.8",
        "1.0.9",
        "1.1.0",
        "1.2.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-111497"
  ],
  "details": "CVE-2026-111497 (\"Node2Shell\") is an out-of-bounds write (CWE-787) in Google\u0027s\nBrotli decoder (c/dec/decode.c). DecodeBlockTypeAndLength() returns an ambiguous\nvalue for an invalid block switch, and the fast decode path discards it\n(CWE-252, unchecked return value), so a crafted Brotli stream makes the decoder\ncontinue on corrupted state and write past the ring buffer. Upstream rates it\nCVSS 4.0 9.2 and classifies the impact as potential remote code execution.\n\nThe vulnerability is in Google\u0027s C library, not in Node.js specifically. The\nPyPI `Brotli` package is Google\u0027s CPython binding and compiles the same\nc/dec/decode.c that has the actual vulnerability. All `Brotli` releases up to\nand including 1.2.0 ship the vulnerable decoder; 1.2.1 contains the upstream\nfix (commit 0ed4268a) and differs from 1.2.0 only in that fix plus a version\nbump.\n\nThe decoder is reached whenever untrusted Brotli data is decompressed. With\n`Brotli` installed, common HTTP clients decode Brotli responses automatically\n(urllib3/requests, httpx with the brotli extra, aiohttp) and services that\naccept `Content-Encoding: br` request bodies decode inbound data, so the flaw\nis reachable from attacker-controlled input.\n",
  "id": "PYSEC-2026-4322",
  "modified": "2026-10-23T00:00:00Z",
  "published": "2026-10-23T00:00:00Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://github.com/google/brotli/commit/0ed4268a4401abcb4472096340477cf4af7d1a2b"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-111497"
    },
    {
      "type": "WEB",
      "url": "https://opensourcemalware.com/blog/node2shell-affects-python"
    },
    {
      "type": "WEB",
      "url": "https://nodejs.org/en/blog/vulnerability/october-2026-security-releases"
    },
    {
      "type": "WEB",
      "url": "https://github.com/google/brotli/releases/tag/v1.2.1"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/Brotli/"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Out-of-bounds write in the Brotli decoder (\"Node2Shell\") also affects the PyPI Brotli package"
}

CVE-2026-111497 (GCVE-0-2026-111497)

Vulnerability from cvelistv5 – Published: 2026-10-22 13:35 – Updated: 2026-10-24 18:07

Title

Out-of-Bounds Write in Google Brotli Decoder

Summary

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.

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-23 00:00 UTC

CWE

CWE-787 - Out-of-bounds Write
CWE-252 - Unchecked Return Value

Assigner

Google CNA under the Google root

CNA scorecard B 77/100 over 39 records in the last 180 days details

References

5 references

URL	Tags
https://nodejs.org/en/blog/vulnerability/october-…	patch
https://github.com/advisories/GHSA-9v8h-qqgm-4m35
http://www.openwall.com/lists/oss-security/2026/1…
https://lists.debian.org/debian-lts-announce/2026…
http://www.openwall.com/lists/oss-security/2026/10/24/6

Impacted products

1 product

Vendor	Product	Version
Google	Brotli	Affected: 1.0.3 , < 1.0.10 (semver) Affected: 1.1.0 , < 1.1.1 (semver) Affected: 1.2.0 , < 1.2.1 (semver)

Date Public

2026-02-27 07:50

Credits

OpenAI Codex Security - Khai Tran and Sylvie Mayer

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-111497",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-23T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-24T03:55:16.808Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-10-24T18:07:52.504Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://github.com/advisories/GHSA-9v8h-qqgm-4m35"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/10/23/25"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2026/10/msg00049.html"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/10/24/6"
          }
        ],
        "title": "CVE Program Container",
        "x_generator": {
          "engine": "ADPogram 0.0.1"
        }
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageName": "github.com/google/brotli",
          "product": "Brotli",
          "repo": "https://github.com/google/brotli",
          "vendor": "Google",
          "versions": [
            {
              "lessThan": "1.0.10",
              "status": "affected",
              "version": "1.0.3",
              "versionType": "semver"
            },
            {
              "lessThan": "1.1.1",
              "status": "affected",
              "version": "1.1.0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.2.1",
              "status": "affected",
              "version": "1.2.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "OpenAI Codex Security - Khai Tran and Sylvie Mayer"
        }
      ],
      "datePublic": "2026-02-27T07:50:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eA buffer overflow vulnerability in the Brotli decoder (\u003ccode\u003ec/dec/decode.c\u003c/code\u003e) 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.\u003cbr\u003e\u003cbr\u003e\u003c/p\u003e\u003cp\u003eUsers 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.\u003cspan\u003e\u003c/span\u003e\u003c/p\u003e"
            }
          ],
          "value": "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.\n\n\n\n\n\nUsers 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."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-100",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-100 Overflow Buffers"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787 Out-of-bounds Write",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-252",
              "description": "CWE-252 Unchecked Return Value",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T14:25:46.551Z",
        "orgId": "14ed7db2-1595-443d-9d34-6215bf890778",
        "shortName": "Google"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "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"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "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."
            }
          ],
          "value": "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": {
        "discovery": "EXTERNAL"
      },
      "title": "Out-of-Bounds Write in Google Brotli Decoder",
      "x_generator": {
        "engine": "Vulnogram 1.0.2"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "14ed7db2-1595-443d-9d34-6215bf890778",
    "assignerShortName": "Google",
    "cveId": "CVE-2026-111497",
    "datePublished": "2026-10-22T13:35:41.975Z",
    "dateReserved": "2026-10-16T09:58:17.790Z",
    "dateUpdated": "2026-10-24T18:07:52.504Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted