{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64558", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.796Z", "datePublished": "2026-07-29T16:31:21.591Z", "dateUpdated": "2026-08-05T12:43:03.921Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:43:03.921Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/pkey: Check length in pkey_pckmo handler implementation\n\nExplicitly check the length of the target buffer in the pkey_pckmo\nimplementation of the key_to_protkey() handler function. The handler\nfunction fails, if the generated output data exceeds the length of the\nprovided target buffer."}], "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 vulnerable path is entered through the PKEY_KBLOB2PROTK/PKEY_KBLOB2PROTK2 ioctls on the /dev/pkey character device, or via an AF_ALG setkey on the paes skciphers. Both require local system access; no network input reaches this code.\nAC:L - A single ioctl with a hand-crafted 176-byte protected-key token (type 0x00, version TOKVER_PROTECTED_KEY, keytype PKEY_KEYTYPE_HMAC_1024, len 160) deterministically triggers the 96-byte overflow; there is no race, no memory-layout dependency, and no hardware or wrapping-key prerequisite since the non-AES branch skips pckmo_verify_protkey().\nPR:L - /dev/pkey is registered as a miscdevice with .mode = 0666 and pkey_unlocked_ioctl() contains no capability or permission check, so any unprivileged local user can reach the bug; the paes/AF_ALG setkey path likewise requires no privileges.\nUI:N - The attacker triggers the overflow entirely on their own via a single ioctl or socket option call; no victim action, mount, or file open is involved.\nS:U - The corruption is confined to the kernel's own stack within the same security authority; exploitation yields kernel privilege escalation rather than crossing a VM, IOMMU, or sandbox boundary.\nC:H - The attacker gains a fully controlled 96-byte out-of-bounds stack write that can clobber adjacent locals, saved pointers and return addresses, which is readily leveraged into arbitrary kernel memory disclosure; the copy also leaves *protkeylen inflated to 160 while the buffer is 64 bytes, feeding an oversized length back to callers.\nI:H - This is an out-of-bounds write of 96 attacker-chosen bytes past the end of a kernel stack object (the last member of struct pkey_kblob2pkey), overwriting saved registers and the return address \u2014 a classic control-flow hijack / local privilege escalation primitive.\nA:H - Smashing the kernel stack past the canary reliably produces a stack-protector panic or an oops on return, and any unprivileged user can repeat it at will to crash the machine."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/s390/crypto/pkey_pckmo.c"], "versions": [{"version": "8fcc231ce3bea12b78bb94b280cdc03cff342435", "lessThan": "02028a24e26d85262ab9c8fc4344e1f3503007fc", "status": "affected", "versionType": "git"}, {"version": "8fcc231ce3bea12b78bb94b280cdc03cff342435", "lessThan": "433e5e70cdc1edf382d28d08a885b22e2b98b7da", "status": "affected", "versionType": "git"}, {"version": "8fcc231ce3bea12b78bb94b280cdc03cff342435", "lessThan": "614aa0491c7a190556c2345dddee0b6f5ed90989", "status": "affected", "versionType": "git"}, {"version": "8fcc231ce3bea12b78bb94b280cdc03cff342435", "lessThan": "1ac287e2af9a9112fe271427ef45eceb26bce8b4", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/s390/crypto/pkey_pckmo.c"], "versions": [{"version": "6.12", "status": "affected"}, {"version": "0", "lessThan": "6.12", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2-rc1", "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": "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-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/02028a24e26d85262ab9c8fc4344e1f3503007fc"}, {"url": "https://git.kernel.org/stable/c/433e5e70cdc1edf382d28d08a885b22e2b98b7da"}, {"url": "https://git.kernel.org/stable/c/614aa0491c7a190556c2345dddee0b6f5ed90989"}, {"url": "https://git.kernel.org/stable/c/1ac287e2af9a9112fe271427ef45eceb26bce8b4"}], "title": "s390/pkey: Check length in pkey_pckmo handler implementation", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"bugzilla": {"description": "kernel: s390/pkey: Check length in pkey_pckmo handler implementation", "id": "2508480", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2508480"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["A flaw was found in the Linux kernel, specifically within the s390/pkey component. This vulnerability occurs because the `pkey_pckmo` handler function does not explicitly check the length of the target buffer. If the generated output data exceeds the provided buffer's length, the handler function fails. This could allow a local attacker to cause a denial of service."], "name": "CVE-2026-64558", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-29T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64558\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64558\nhttps://lore.kernel.org/linux-cve-announce/2026072912-CVE-2026-64558-7352@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8fcc231ce3bea12b78bb94b280cdc03cff342435,02028a24e26d85262ab9c8fc4344e1f3503007fc)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8fcc231ce3bea12b78bb94b280cdc03cff342435,433e5e70cdc1edf382d28d08a885b22e2b98b7da)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8fcc231ce3bea12b78bb94b280cdc03cff342435,614aa0491c7a190556c2345dddee0b6f5ed90989)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8fcc231ce3bea12b78bb94b280cdc03cff342435,1ac287e2af9a9112fe271427ef45eceb26bce8b4)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.12"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.12)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.97,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.40,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.5,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-29T17:30:04.079252+00:00", "updated": "2026-07-29T17:30:04.079285+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}