{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59980","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-07T19:41:00.004Z","datePublished":"2026-09-23T22:07:35.095Z","dateUpdated":"2026-09-24T13:25:08.900Z"},"containers":{"cna":{"title":"hpack: Unbounded variable integer decoding can cause run-away computation on malformed input","problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"}}],"references":[{"name":"https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2","tags":["x_refsource_CONFIRM"],"url":"https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2"},{"name":"https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c","tags":["x_refsource_MISC"],"url":"https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c"},{"name":"https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a","tags":["x_refsource_MISC"],"url":"https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a"},{"name":"https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403","tags":["x_refsource_MISC"],"url":"https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403"}],"affected":[{"vendor":"python-hyper","product":"hpack","versions":[{"version":"< 4.2.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-09-23T22:07:35.095Z"},"descriptions":[{"lang":"en","value":"hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use."}],"source":{"advisory":"GHSA-8v8h-hg4w-mvq2","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-24T13:24:31.887152Z","id":"CVE-2026-59980","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-24T13:25:08.900Z"}}]}}