{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31637", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.125Z", "datePublished": "2026-04-24T14:44:51.364Z", "dateUpdated": "2026-10-16T15:20:17.706Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:24:01.829Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: reject undecryptable rxkad response tickets\n\nrxkad_decrypt_ticket() decrypts the RXKAD response ticket and then\nparses the buffer as plaintext without checking whether\ncrypto_skcipher_decrypt() succeeded.\n\nA malformed RESPONSE can therefore use a non-block-aligned ticket\nlength, make the decrypt operation fail, and still drive the ticket\nparser with attacker-controlled bytes.\n\nCheck the decrypt result and abort the connection with RXKADBADTICKET\nwhen ticket decryption fails." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable path is reached by remote RxRPC RESPONSE packets over UDP to a listening AF_RXRPC service connection.\nAC:L - An attacker can initiate the connection, receive the server challenge, and craft a non-block-aligned ticket plus matching response using an attacker-chosen session key; no race or uncontrolled condition is required.\nPR:N - The flaw is in the authentication handshake before client credentials are validated, so a network attacker needs no prior privileges or valid rxkad ticket.\nUI:N - Exploitation only requires sending protocol packets to the service; no victim user action is needed.\nS:U - The impact remains within the kernel/RxRPC service security authority and does not cross a VM, IOMMU, or similar security boundary.\nC:H - The bug can bypass rxkad authentication and let an unauthenticated peer access data exposed by a protected RxRPC service in the highest reasonable deployment.\nI:H - A forged authenticated connection can issue arbitrary service RPCs and choose/downgrade the connection security level, enabling unauthorized modification of protected service state.\nA:H - In a severe RxRPC service deployment, the same authentication bypass can be used to invoke destructive or service-disrupting authenticated operations repeatedly over the network." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/rxrpc/rxkad.c" ], "versions": [ { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "252157d939d179b5d767cb860ff8fa7f8723b67a", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "a75b3b361dd481d942c5f259a82d59718a41092c", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "b3a808cd0790b5075aaa2bc3588edf02cd71d352", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "a149dcae23309df9de1c3b6b5d468610ef5ab7de", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "22f6258e7b31dba9bf88dce4e3ee7f0f20072e60", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "58fcd1b156152613ba00a064a129fb69507ddd7d", "status": "affected", "versionType": "git" }, { "version": "17926a79320afa9b95df6b977b40cca6d8713cea", "lessThan": "fe4447cd95623b1cfacc15f280aab73a6d7340b2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/rxrpc/rxkad.c" ], "versions": [ { "version": "2.6.22", "status": "affected" }, { "version": "0", "lessThan": "2.6.22", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.135", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.82", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.23", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.13", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "6.6.135" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "6.12.82" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "6.18.23" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "6.19.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.22", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/252157d939d179b5d767cb860ff8fa7f8723b67a" }, { "url": "https://git.kernel.org/stable/c/a75b3b361dd481d942c5f259a82d59718a41092c" }, { "url": "https://git.kernel.org/stable/c/b3a808cd0790b5075aaa2bc3588edf02cd71d352" }, { "url": "https://git.kernel.org/stable/c/47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a" }, { "url": "https://git.kernel.org/stable/c/a149dcae23309df9de1c3b6b5d468610ef5ab7de" }, { "url": "https://git.kernel.org/stable/c/22f6258e7b31dba9bf88dce4e3ee7f0f20072e60" }, { "url": "https://git.kernel.org/stable/c/58fcd1b156152613ba00a064a129fb69507ddd7d" }, { "url": "https://git.kernel.org/stable/c/fe4447cd95623b1cfacc15f280aab73a6d7340b2" } ], "title": "rxrpc: reject undecryptable rxkad response tickets", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-10-15T01:17:25.667Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-784472.html" } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-31637", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T15:11:24.761157Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T15:20:17.706Z" } } ] } }