{"id":"CVE-2026-89476","title":"sctp: fix stream->outcnt underflow on duplicate RECONF responses","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix stream->outcnt underflow on duplicate RECONF responses\n\nA cached RECONF chunk may contain more than one request parameter.  A\nduplicate response can therefore…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-191"],"vendor":"Linux","product":"Linux","affected":["Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 041f7df5a929d3e7435dd8387e8ea17f2d412b7d","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 59f61c39cb99ee1737bd742a20094fe5653389bb","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 793519e343867ee9a3e84f6cac07f81f2aec7b5d","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 092acd3c55a4077b00489064615d8d2d898daf91","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 2d867663c563e8009257b9edf9c8ec75d9bbf19a","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < d02a5794c3deedcb8476d017fcee2b7aaedab2e1","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68","Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e","Linux 4.12"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T19:22:19.523303Z"},"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:47:25.179Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89476","references":[{"url":"https://git.kernel.org/stable/c/041f7df5a929d3e7435dd8387e8ea17f2d412b7d"},{"url":"https://git.kernel.org/stable/c/59f61c39cb99ee1737bd742a20094fe5653389bb"},{"url":"https://git.kernel.org/stable/c/793519e343867ee9a3e84f6cac07f81f2aec7b5d"},{"url":"https://git.kernel.org/stable/c/092acd3c55a4077b00489064615d8d2d898daf91"},{"url":"https://git.kernel.org/stable/c/2d867663c563e8009257b9edf9c8ec75d9bbf19a"},{"url":"https://git.kernel.org/stable/c/d02a5794c3deedcb8476d017fcee2b7aaedab2e1"},{"url":"https://git.kernel.org/stable/c/8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68"},{"url":"https://git.kernel.org/stable/c/3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89476.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89476"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532035"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89476"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89476"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89476.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00696,"epssPercentile":0.52818,"scores":{"cna":7.5,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.453Z","slug":"CVE-2026-89476","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix stream->outcnt underflow on duplicate RECONF responses\n\nA cached RECONF chunk may contain more than one request parameter.  A\nduplicate response can therefore find and process the same ADD_OUT request\nagain while another parameter is still outstanding, rolling back outcnt\ntwice and possibly underflowing it.\n\nTrack outstanding request types as bits and clear each bit after its first\nresponse.  Later responses for the same request are then ignored.\n\n## Affected\n\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 041f7df5a929d3e7435dd8387e8ea17f2d412b7d`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 59f61c39cb99ee1737bd742a20094fe5653389bb`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 793519e343867ee9a3e84f6cac07f81f2aec7b5d`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 092acd3c55a4077b00489064615d8d2d898daf91`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 2d867663c563e8009257b9edf9c8ec75d9bbf19a`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < d02a5794c3deedcb8476d017fcee2b7aaedab2e1`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68`\n- `Linux >= 11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 < 3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e`\n- `Linux 4.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89476.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":223320,"id":"CVE-2026-89476","ts":1792180055550,"field":"cvss","old":"7","new":"7.5"},{"seq":202756,"id":"CVE-2026-89476","ts":1789403715646,"field":"cvss","old":"7.5","new":"7"},{"seq":198034,"id":"CVE-2026-89476","ts":1789384321481,"field":"cvss","old":"5.9","new":"7.5"},{"seq":198033,"id":"CVE-2026-89476","ts":1789384321481,"field":"severity","old":"medium","new":"high"},{"seq":183788,"id":"CVE-2026-89476","ts":1789356677393,"field":"cvss","old":"7.5","new":"5.9"},{"seq":183787,"id":"CVE-2026-89476","ts":1789356677393,"field":"severity","old":"high","new":"medium"},{"seq":153252,"id":"CVE-2026-89476","ts":1789285349747,"field":"cvss","old":null,"new":"7.5"},{"seq":153251,"id":"CVE-2026-89476","ts":1789285349747,"field":"severity","old":"none","new":"high"},{"seq":109650,"id":"CVE-2026-89476","ts":1789183732790,"field":"cvss","old":null,"new":"5.9"},{"seq":109649,"id":"CVE-2026-89476","ts":1789183732790,"field":"severity","old":"none","new":"medium"}]}