{"id":"CVE-2026-23455","state":"PUBLISHED","title":"netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it by 1 to skip the protocol discriminator\nbyte before passing it to DecodeH323_UserInformation(). If the encoded\nlength is 0, the decrement wraps to -1, which is then passed as a\nlarge value to the decoder, leading to an out-of-bounds read.\n\nAdd a check to ensure len is positive after the decrement.","publishedAt":"2026-04-03T15:15:36.869Z","updatedAt":"2026-10-19T18:35:44.554Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"2121f5fbe88daff0f1fc5bc47d359426c74b86b0","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"65fa92f79677858b14b9e4b7275f26639afe2710","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"495e97af9e7249ee02b72bb1d0848a6efc3700f4","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"f5e4f4e4cdb75ec36802059a94195a31f193da60","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"633e8f87dad32263f6a57dccdb873f042c062111","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"b652b05d51003ac074b912684f9ec7486231717b","versionType":"git"},{"version":"5e35941d990123f155b02d5663e51a24f816b6f3","status":"affected","lessThan":"f173d0f4c0f689173f8cdac79991043a4a89bf66","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_h323_asn1.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.17","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.167","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.20","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.10","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_h323_asn1.c"]}],"references":["https://git.kernel.org/stable/c/2121f5fbe88daff0f1fc5bc47d359426c74b86b0","https://git.kernel.org/stable/c/65fa92f79677858b14b9e4b7275f26639afe2710","https://git.kernel.org/stable/c/495e97af9e7249ee02b72bb1d0848a6efc3700f4","https://git.kernel.org/stable/c/f5e4f4e4cdb75ec36802059a94195a31f193da60","https://git.kernel.org/stable/c/633e8f87dad32263f6a57dccdb873f042c062111","https://git.kernel.org/stable/c/9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8","https://git.kernel.org/stable/c/b652b05d51003ac074b912684f9ec7486231717b","https://git.kernel.org/stable/c/f173d0f4c0f689173f8cdac79991043a4a89bf66","https://cert-portal.siemens.com/productcert/html/ssa-082556.html","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23455.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23455","state":"PUBLISHED","datePublished":"2026-04-03T15:15:36.869Z","dateUpdated":"2026-10-19T18:35:44.554Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:46.020Z"},"containers":{"cna":{"title":"netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it by 1 to skip the protocol discriminator\nbyte before passing it to DecodeH323_UserInformation(). 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