{"id":"CVE-2026-63823","state":"PUBLISHED","title":"keys: Pin request_key_auth payload in instantiate paths","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nkeys: Pin request_key_auth payload in instantiate paths\n\nA: request_key()       B: KEYCTL_INSTANTIATE_IOV\n================       =========================\n\ncreate auth key\nstore rka in auth key\nwait for helper\n                       get auth key\n                       load rka from auth key\n                       copy user payload\n                       sleep on #PF\n\nhelper completed\ndetach and free rka\ndestroy auth key\n                       wake up\n                       use rka->target_key\n                       **USE-AFTER-FREE**\n\nGive request_key_auth payloads a refcount.  Take a payload reference while\nauthkey->sem stabilizes the payload and revocation state.  Hold that\nreference across the instantiate and reject paths.  Drop the auth key\nowning reference from revoke and destroy.\n\n[jarkko: Replaced the first two paragraphs of text with an actual\n concurrency scenario.]","publishedAt":"2026-07-19T12:02:19.847Z","updatedAt":"2026-10-19T20:07:48.726Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"d8274181b0f28d450b42489723a5ba81042158d7","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"4982bfabce6b33b3c9eddb4fb900fe5568b7cf91","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"708709c65a1832a99b0eef8ae46e343ddaca3d06","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"35ab4db86774d82389e4b9559e26ab7f68d8e395","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"f9b68632ac93cc742f2e411021c4dbfe452ea0c2","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"7216ce8cb12fee44e309503955bb83806b106129","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"fd15b457a86939c38aa12116adabd8ff686c5e51","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/keys/request_key_auth-type.h","security/keys/internal.h","security/keys/keyctl.c","security/keys/request_key_auth.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.16","versionType":"semver"},{"version":"5.10.260","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.211","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.177","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.144","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.95","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.38","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.3","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/keys/request_key_auth-type.h","security/keys/internal.h","security/keys/keyctl.c","security/keys/request_key_auth.c"]}],"references":["https://git.kernel.org/stable/c/d8274181b0f28d450b42489723a5ba81042158d7","https://git.kernel.org/stable/c/4982bfabce6b33b3c9eddb4fb900fe5568b7cf91","https://git.kernel.org/stable/c/708709c65a1832a99b0eef8ae46e343ddaca3d06","https://git.kernel.org/stable/c/35ab4db86774d82389e4b9559e26ab7f68d8e395","https://git.kernel.org/stable/c/f9b68632ac93cc742f2e411021c4dbfe452ea0c2","https://git.kernel.org/stable/c/7216ce8cb12fee44e309503955bb83806b106129","https://git.kernel.org/stable/c/83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f","https://git.kernel.org/stable/c/fd15b457a86939c38aa12116adabd8ff686c5e51"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63823.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63823","state":"PUBLISHED","datePublished":"2026-07-19T12:02:19.847Z","dateUpdated":"2026-10-19T20:07:48.726Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.014Z"},"containers":{"cna":{"title":"keys: Pin request_key_auth payload in instantiate paths","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nkeys: Pin request_key_auth payload in instantiate paths\n\nA: request_key()       B: KEYCTL_INSTANTIATE_IOV\n================       =========================\n\ncreate auth key\nstore rka in auth key\nwait for helper\n                       get auth key\n                       load rka from auth key\n                       copy user payload\n                       sleep on #PF\n\nhelper completed\ndetach and free rka\ndestroy auth key\n                       wake up\n                       use rka->target_key\n                       **USE-AFTER-FREE**\n\nGive request_key_auth payloads a refcount.  Take a payload reference while\nauthkey->sem stabilizes the payload and revocation state.  Hold that\nreference across the instantiate and reject paths.  Drop the auth key\nowning reference from revoke and destroy.\n\n[jarkko: Replaced the first two paragraphs of text with an actual\n concurrency scenario.]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"d8274181b0f28d450b42489723a5ba81042158d7","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"4982bfabce6b33b3c9eddb4fb900fe5568b7cf91","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"708709c65a1832a99b0eef8ae46e343ddaca3d06","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"35ab4db86774d82389e4b9559e26ab7f68d8e395","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"f9b68632ac93cc742f2e411021c4dbfe452ea0c2","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"7216ce8cb12fee44e309503955bb83806b106129","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f","versionType":"git"},{"version":"b5f545c880a2a47947ba2118b2509644ab7a2969","status":"affected","lessThan":"fd15b457a86939c38aa12116adabd8ff686c5e51","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/keys/request_key_auth-type.h","security/keys/internal.h","security/keys/keyctl.c","security/keys/request_key_auth.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.16","versionType":"semver"},{"version":"5.10.260","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.211","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.177","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.144","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.95","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.38","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.3","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/keys/request_key_auth-type.h","security/keys/internal.h","security/keys/keyctl.c","security/keys/request_key_auth.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/d8274181b0f28d450b42489723a5ba81042158d7"},{"url":"https://git.kernel.org/stable/c/4982bfabce6b33b3c9eddb4fb900fe5568b7cf91"},{"url":"https://git.kernel.org/stable/c/708709c65a1832a99b0eef8ae46e343ddaca3d06"},{"url":"https://git.kernel.org/stable/c/35ab4db86774d82389e4b9559e26ab7f68d8e395"},{"url":"https://git.kernel.org/stable/c/f9b68632ac93cc742f2e411021c4dbfe452ea0c2"},{"url":"https://git.kernel.org/stable/c/7216ce8cb12fee44e309503955bb83806b106129"},{"url":"https://git.kernel.org/stable/c/83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f"},{"url":"https://git.kernel.org/stable/c/fd15b457a86939c38aa12116adabd8ff686c5e51"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through local `request_key()` and `keyctl()` syscalls (`KEYCTL_ASSUME_AUTHORITY`, `KEYCTL_INSTANTIATE`, `KEYCTL_INSTANTIATE_IOV`, `KEYCTL_REJECT`); there is no network, adjacent-radio, or physical-device entry path.\nAC:L - Exploitation is a race the attacker orchestrates by calling `request_key()` and concurrently driving `KEYCTL_INSTANTIATE_IOV` with a user buffer that page-faults during `copy_from_iter_full()`, while a second helper thread or completion path revokes/frees the auth payload.\nPR:L - Any unprivileged local user can invoke `request_key()` and the affected `keyctl` instantiate/reject operations in the spawned helper context; no real-root or non-userns capability is required.\nUI:N - Exploitation does not depend on a victim performing an action beyond the attacker’s own syscall activity and helper process setup.\nS:U - Impact is kernel memory corruption and local privilege escalation within the same kernel security domain, not a VM-guest-to-host or IOMMU boundary escape.\nC:H - This is a heap use-after-free of `struct request_key_auth`; after free the code dereferences `rka->target_key` and related fields, enabling attacker-controlled reuse and arbitrary kernel memory disclosure.\nI:H - The UAF corrupts trusted kernel pointers (`target_key`, `dest_keyring`) used in `key_instantiate_and_link()`, which can be turned into arbitrary kernel writes and local privilege escalation.\nA:H - Use-after-free of kernel heap objects can cause kernel oops/panic during post-fault dereferences, and is independently severe even before full exploitation."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:51:31.393Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"5.10.260"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"5.15.211"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"6.1.177"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"6.6.144"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"6.12.95"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"6.18.38"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"7.1.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.16","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-63823","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:31:09.788460Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:07:48.726Z"}}]}}}