{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-63823", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.014Z", "datePublished": "2026-07-19T12:02:19.847Z", "dateUpdated": "2026-08-17T04:51:31.393Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:51:31.393Z" }, "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.]" } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "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" ], "versions": [ { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "d8274181b0f28d450b42489723a5ba81042158d7", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "4982bfabce6b33b3c9eddb4fb900fe5568b7cf91", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "708709c65a1832a99b0eef8ae46e343ddaca3d06", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "35ab4db86774d82389e4b9559e26ab7f68d8e395", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "f9b68632ac93cc742f2e411021c4dbfe452ea0c2", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "7216ce8cb12fee44e309503955bb83806b106129", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f", "status": "affected", "versionType": "git" }, { "version": "b5f545c880a2a47947ba2118b2509644ab7a2969", "lessThan": "fd15b457a86939c38aa12116adabd8ff686c5e51", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "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" ], "versions": [ { "version": "2.6.16", "status": "affected" }, { "version": "0", "lessThan": "2.6.16", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.260", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.211", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.177", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.144", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.95", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.38", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.3", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "2.6.16", "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" } ] } ] } ], "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" } ], "title": "keys: Pin request_key_auth payload in instantiate paths", "x_generator": { "engine": "bippy-1.2.0" } } } }