{"id":"CVE-2026-116579","state":"PUBLISHED","title":"Autobahn Python: permessage-brotli inflates a whole frame before maxMessagePayloadSize is checked (incomplete fix of GHSA-hxp9-w8x3-p566)","description":"Autobahn Python is a WebSocket and WAMP implementation for Python that supports Twisted and asyncio. From 26.7.1 until 26.10.1, PerMessageBrotli.decompress_message_data in compress_brotli.py calls the Brotli decompressor without an output limit and checks maxMessagePayloadSize only after a complete frame has been inflated. An unauthenticated WebSocket client can send a small, highly compressed frame that allocates hundreds of MiB before rejection, causing memory-exhaustion denial of service on servers that enable the opt-in permessage-brotli feature through the compress extra. Deflate and bzip2 already enforce the remaining output budget and are outside this residual vulnerability. This issue is fixed in version 26.10.1.","publishedAt":"2026-10-26T20:29:22.906Z","updatedAt":"2026-10-27T14:18:18.772Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["crossbario autobahn-python"],"affected":[{"vendor":"crossbario","product":"autobahn-python","versions":[{"version":">= 26.7.1, < 26.10.1","status":"affected"}]}],"references":["https://github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg-3x7m","https://github.com/crossbario/autobahn-python/pull/1987","https://github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb892840124c24d16f1","https://github.com/crossbario/autobahn-python/releases/tag/v26_10_1"],"weaknesses":["CWE-409","CWE-770"],"ingestedAt":"2026-10-29T20:10:43.281Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/116xxx/CVE-2026-116579.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-116579","state":"PUBLISHED","datePublished":"2026-10-26T20:29:22.906Z","dateUpdated":"2026-10-27T14:18:18.772Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-26T15:03:39.035Z"},"containers":{"cna":{"title":"Autobahn Python: permessage-brotli inflates a whole frame before maxMessagePayloadSize is checked (incomplete fix of GHSA-hxp9-w8x3-p566)","descriptions":[{"lang":"en","value":"Autobahn Python is a WebSocket and WAMP implementation for Python that supports Twisted and asyncio. From 26.7.1 until 26.10.1, PerMessageBrotli.decompress_message_data in compress_brotli.py calls the Brotli decompressor without an output limit and checks maxMessagePayloadSize only after a complete frame has been inflated. An unauthenticated WebSocket client can send a small, highly compressed frame that allocates hundreds of MiB before rejection, causing memory-exhaustion denial of service on servers that enable the opt-in permessage-brotli feature through the compress extra. Deflate and bzip2 already enforce the remaining output budget and are outside this residual vulnerability. This issue is fixed in version 26.10.1."}],"affected":[{"vendor":"crossbario","product":"autobahn-python","versions":[{"version":">= 26.7.1, < 26.10.1","status":"affected"}]}],"references":[{"url":"https://github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg-3x7m","name":"https://github.com/crossbario/autobahn-python/security/advisories/GHSA-pjh6-c8mg-3x7m","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/crossbario/autobahn-python/pull/1987","name":"https://github.com/crossbario/autobahn-python/pull/1987","tags":["x_refsource_MISC"]},{"url":"https://github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb892840124c24d16f1","name":"https://github.com/crossbario/autobahn-python/commit/a41442bbee4f6126a8ce1bb892840124c24d16f1","tags":["x_refsource_MISC"]},{"url":"https://github.com/crossbario/autobahn-python/releases/tag/v26_10_1","name":"https://github.com/crossbario/autobahn-python/releases/tag/v26_10_1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-409","lang":"en","description":"CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-26T20:29:22.906Z"},"source":{"advisory":"GHSA-pjh6-c8mg-3x7m","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-27T13:41:50.957164Z","id":"CVE-2026-116579","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-27T14:18:18.772Z"}}]}}}