{"id":"CVE-2026-31696","state":"PUBLISHED","title":"rxrpc: Fix missing validation of ticket length in non-XDR key preparsing","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix missing validation of ticket length in non-XDR key preparsing\n\nIn rxrpc_preparse(), there are two paths for parsing key payloads: the\nXDR path (for large payloads) and the non-XDR path (for payloads <= 28\nbytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly\nvalidates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR\npath fails to do so.\n\nThis allows an unprivileged user to provide a very large ticket length.\nWhen this key is later read via rxrpc_read(), the total\ntoken size (toksize) calculation results in a value that exceeds\nAFSTOKEN_LENGTH_MAX, triggering a WARN_ON().\n\n[ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc]\n\nFix this by adding a check in the non-XDR parsing path of rxrpc_preparse()\nto ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX,\nbringing it into parity with the XDR parsing logic.","publishedAt":"2026-05-01T13:55:57.485Z","updatedAt":"2026-10-15T01:17:54.785Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"44714dfda386884919ba366411880b6fb3c3efd3","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"41a117dd80371343babc52198d1114e83eb37627","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"9a397aa9b5e53ca63d4d6aefb542832eca389618","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"1fa36cf495b0023e8475d038535c05e4063211e1","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"4458757c020592a3094366e0fb20457383b42f92","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"ce383ba615339f8eaec646a166d2c2b015bb5ca0","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"a1be1c9ece26cea69654f28b255ff9a7906b897b","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"ac33733b10b484d666f97688561670afd5861383","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rxrpc/key.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.17","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.84","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.25","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.2","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rxrpc/key.c"]}],"references":["https://git.kernel.org/stable/c/44714dfda386884919ba366411880b6fb3c3efd3","https://git.kernel.org/stable/c/41a117dd80371343babc52198d1114e83eb37627","https://git.kernel.org/stable/c/9a397aa9b5e53ca63d4d6aefb542832eca389618","https://git.kernel.org/stable/c/1fa36cf495b0023e8475d038535c05e4063211e1","https://git.kernel.org/stable/c/4458757c020592a3094366e0fb20457383b42f92","https://git.kernel.org/stable/c/ce383ba615339f8eaec646a166d2c2b015bb5ca0","https://git.kernel.org/stable/c/a1be1c9ece26cea69654f28b255ff9a7906b897b","https://git.kernel.org/stable/c/ac33733b10b484d666f97688561670afd5861383","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31696.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31696","state":"PUBLISHED","datePublished":"2026-05-01T13:55:57.485Z","dateUpdated":"2026-10-15T01:17:54.785Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.131Z"},"containers":{"cna":{"title":"rxrpc: Fix missing validation of ticket length in non-XDR key preparsing","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix missing validation of ticket length in non-XDR key preparsing\n\nIn rxrpc_preparse(), there are two paths for parsing key payloads: the\nXDR path (for large payloads) and the non-XDR path (for payloads <= 28\nbytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly\nvalidates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR\npath fails to do so.\n\nThis allows an unprivileged user to provide a very large ticket length.\nWhen this key is later read via rxrpc_read(), the total\ntoken size (toksize) calculation results in a value that exceeds\nAFSTOKEN_LENGTH_MAX, triggering a WARN_ON().\n\n[ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc]\n\nFix this by adding a check in the non-XDR parsing path of rxrpc_preparse()\nto ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX,\nbringing it into parity with the XDR parsing logic."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"44714dfda386884919ba366411880b6fb3c3efd3","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"41a117dd80371343babc52198d1114e83eb37627","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"9a397aa9b5e53ca63d4d6aefb542832eca389618","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"1fa36cf495b0023e8475d038535c05e4063211e1","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"4458757c020592a3094366e0fb20457383b42f92","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"ce383ba615339f8eaec646a166d2c2b015bb5ca0","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"a1be1c9ece26cea69654f28b255ff9a7906b897b","versionType":"git"},{"version":"8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247","status":"affected","lessThan":"ac33733b10b484d666f97688561670afd5861383","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rxrpc/key.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.17","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.84","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.25","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.2","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rxrpc/key.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/44714dfda386884919ba366411880b6fb3c3efd3"},{"url":"https://git.kernel.org/stable/c/41a117dd80371343babc52198d1114e83eb37627"},{"url":"https://git.kernel.org/stable/c/9a397aa9b5e53ca63d4d6aefb542832eca389618"},{"url":"https://git.kernel.org/stable/c/1fa36cf495b0023e8475d038535c05e4063211e1"},{"url":"https://git.kernel.org/stable/c/4458757c020592a3094366e0fb20457383b42f92"},{"url":"https://git.kernel.org/stable/c/ce383ba615339f8eaec646a166d2c2b015bb5ca0"},{"url":"https://git.kernel.org/stable/c/a1be1c9ece26cea69654f28b255ff9a7906b897b"},{"url":"https://git.kernel.org/stable/c/ac33733b10b484d666f97688561670afd5861383"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-14T17:43:27.449Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"5.10.258"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"5.15.209"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"6.6.136"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"6.12.84"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"6.18.25"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"7.0.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.17","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:17:54.785Z"},"x_adpType":"supplier"}]}}}