{"id":"CVE-2026-64559","state":"PUBLISHED","title":"s390/pkey: Check length in PKEY_VERIFYPROTK ioctl","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/pkey: Check length in PKEY_VERIFYPROTK ioctl\n\nExplicitly check the buffer length request structure provided by\nuser-space and fail, if it exceeds the buffer size.","publishedAt":"2026-07-29T16:31:22.195Z","updatedAt":"2026-10-19T20:48:41.365Z","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":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"0a9e34ccbe772b8f321388cdbdf4f22b94e513e7","versionType":"git"},{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"693bf91d4db134f9b1c2840c8e287eee3d993bac","versionType":"git"},{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"7e7e03848c918aa0acad5ffd75d929e3afec1554","versionType":"git"},{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/s390/crypto/pkey_api.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","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":["drivers/s390/crypto/pkey_api.c"]}],"references":["https://git.kernel.org/stable/c/0a9e34ccbe772b8f321388cdbdf4f22b94e513e7","https://git.kernel.org/stable/c/693bf91d4db134f9b1c2840c8e287eee3d993bac","https://git.kernel.org/stable/c/7e7e03848c918aa0acad5ffd75d929e3afec1554","https://git.kernel.org/stable/c/b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64559.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64559","state":"PUBLISHED","datePublished":"2026-07-29T16:31:22.195Z","dateUpdated":"2026-10-19T20:48:41.365Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.796Z"},"containers":{"cna":{"title":"s390/pkey: Check length in PKEY_VERIFYPROTK ioctl","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/pkey: Check length in PKEY_VERIFYPROTK ioctl\n\nExplicitly check the buffer length request structure provided by\nuser-space and fail, if it exceeds the buffer size."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"0a9e34ccbe772b8f321388cdbdf4f22b94e513e7","versionType":"git"},{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"693bf91d4db134f9b1c2840c8e287eee3d993bac","versionType":"git"},{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"7e7e03848c918aa0acad5ffd75d929e3afec1554","versionType":"git"},{"version":"8fcc231ce3bea12b78bb94b280cdc03cff342435","status":"affected","lessThan":"b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/s390/crypto/pkey_api.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","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":["drivers/s390/crypto/pkey_api.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0a9e34ccbe772b8f321388cdbdf4f22b94e513e7"},{"url":"https://git.kernel.org/stable/c/693bf91d4db134f9b1c2840c8e287eee3d993bac"},{"url":"https://git.kernel.org/stable/c/7e7e03848c918aa0acad5ffd75d929e3afec1554"},{"url":"https://git.kernel.org/stable/c/b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970"}],"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 vulnerability is reached only through the PKEY_VERIFYPROTK ioctl on the /dev/pkey character device, which requires local access to the system. There is no network-facing path to this code.\nAC:L - Triggering is fully deterministic — a single ioctl with protkey.len set to 0x20000010 wraps the u32 multiplication to a legal 128-bit keytype and drives the unchecked memcpy; no race, timing, or uncontrollable memory-layout condition is involved.\nPR:L - The pkey miscdevice is registered with .mode = 0666 and neither the open handler nor pkey_unlocked_ioctl performs any capability check, so any unprivileged local user (including a normal shell user on a shared IBM Z LPAR or z/VM guest) can issue the ioctl.\nUI:N - The attacker performs the entire attack via its own ioctl call; no action by any other user or administrator is needed.\nS:U - The out-of-bounds read and write are confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The unchecked memcpy performs a huge out-of-bounds read that walks off the 64-byte on-stack protkey buffer through the entire kernel stack, relocating arbitrary kernel stack contents — including protected key material handled by this crypto driver — into heap objects, an unbounded kernel memory disclosure primitive.\nI:H - This is a massive slab out-of-bounds write into an 80-byte kmalloc-96 allocation whose first 64 bytes are entirely attacker-supplied and whose subsequent bytes come from groomable kernel-stack data, corrupting adjacent slab objects and providing a heap-overflow primitive suitable for control-flow hijacking.\nA:H - The smallest length that bypasses the keytype check requests a 512 MB copy, so the source pointer inevitably hits the VMAP_STACK guard page, producing an unhandled kernel fault/oops and panic after wide-scale heap corruption — a guaranteed, repeatable denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:57:37.809Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64559","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:42:43.749651Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:48:41.365Z"}}]}}}