{"id":"CVE-2026-64208","state":"PUBLISHED","title":"crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks\n\nChange the krb5 crypto library to provide facilities to precheck the length\nof the message about to be decrypted or verified.\n\nFix AF_RXRPC to make use of this to validate DATA packets secured with\nRxGK.","publishedAt":"2026-07-24T15:23:00.113Z","updatedAt":"2026-08-05T12:40:02.002Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a","status":"affected","lessThan":"585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff","versionType":"git"},{"version":"9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a","status":"affected","lessThan":"9217017f4bce53dddb8d547837f1f707045d64ad","versionType":"git"},{"version":"9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a","status":"affected","lessThan":"2b50aceafe6606ea52ed42aadd1b4d44a188aade","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["Documentation/crypto/krb5.rst","crypto/krb5/krb5_api.c","include/crypto/krb5.h","include/trace/events/rxrpc.h","net/rxrpc/rxgk.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","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":["Documentation/crypto/krb5.rst","crypto/krb5/krb5_api.c","include/crypto/krb5.h","include/trace/events/rxrpc.h","net/rxrpc/rxgk.c"]}],"references":["https://git.kernel.org/stable/c/585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff","https://git.kernel.org/stable/c/9217017f4bce53dddb8d547837f1f707045d64ad","https://git.kernel.org/stable/c/2b50aceafe6606ea52ed42aadd1b4d44a188aade"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64208.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64208","state":"PUBLISHED","datePublished":"2026-07-24T15:23:00.113Z","dateUpdated":"2026-08-05T12:40:02.002Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.769Z"},"containers":{"cna":{"title":"crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks\n\nChange the krb5 crypto library to provide facilities to precheck the length\nof the message about to be decrypted or verified.\n\nFix AF_RXRPC to make use of this to validate DATA packets secured with\nRxGK."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a","status":"affected","lessThan":"585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff","versionType":"git"},{"version":"9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a","status":"affected","lessThan":"9217017f4bce53dddb8d547837f1f707045d64ad","versionType":"git"},{"version":"9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a","status":"affected","lessThan":"2b50aceafe6606ea52ed42aadd1b4d44a188aade","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["Documentation/crypto/krb5.rst","crypto/krb5/krb5_api.c","include/crypto/krb5.h","include/trace/events/rxrpc.h","net/rxrpc/rxgk.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","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":["Documentation/crypto/krb5.rst","crypto/krb5/krb5_api.c","include/crypto/krb5.h","include/trace/events/rxrpc.h","net/rxrpc/rxgk.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff"},{"url":"https://git.kernel.org/stable/c/9217017f4bce53dddb8d547837f1f707045d64ad"},{"url":"https://git.kernel.org/stable/c/2b50aceafe6606ea52ed42aadd1b4d44a188aade"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - Attacker-controlled RxRPC DATA packets reach the vulnerable RxGK verifier over UDP. A malicious contacted server can exercise the client receive path without network proximity.\nAC:L - A single deliberately short packet triggers the faulty length handling without a race or uncontrollable condition. Visible RxRPC header fields allow the peer to target an active call reliably.\nPR:N - The length handling occurs before MIC verification or decryption authenticates the packet. A malicious RxRPC server therefore needs no valid Kerberos key or credentials.\nUI:N - No human action is required once an application or mounted AFS/YFS client communicates over the RxGK connection. Packet processing and call termination occur automatically.\nS:U - The vulnerable RxRPC processing and resulting impact remain within the host kernel's security authority. No VM, sandbox, or IOMMU boundary is crossed.\nC:N - The underlying Kerberos implementations reject blobs shorter than their cryptographic overhead before accessing packet data. No out-of-bounds read or information disclosure is supported by the affected path.\nI:N - The malformed length does not produce an out-of-bounds write or attacker-controlled modification. Existing post-decryption checks prevent reading or applying a truncated inner header.\nA:H - A short unauthenticated packet aborts the active RxRPC call, and repeated injections can continuously deny RxGK-protected AFS/YFS operations. This can make a critical network filesystem or dependent service unavailable."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:40:02.002Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}