CVE-2026-64439

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64439", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.788Z", "datePublished": "2026-07-25T08:51:12.422Z", "dateUpdated": "2026-08-17T04:55:40.947Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:55:40.947Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: krb5 - filter out async aead implementations at alloc\n\nkrb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and\nrfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL\ncompletion callback and treat any negative return from\ncrypto_aead_{encrypt,decrypt}() as terminal, falling through to\nkfree_sensitive(buffer). When the encrypt_name resolves to an\nasync AEAD instance the request returns -EINPROGRESS, the buffer\nis freed while the backend's worker still holds a pointer, and the\nworker dereferences the freed slab on completion.\n\nKASAN report under UML+SLUB with a synthetic async aead backend\nbound to krb5->encrypt_name:\n\n BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7\n\nThe helpers were written synchronously, so filter the async\ninstances out at allocation time instead of plumbing\ncrypto_wait_req() through every call site.\n\nReachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and\nnet/ceph/crypto.c on systems with an async AEAD provider bound to\nthe krb5 enctype name."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - An unauthenticated remote peer can reach the vulnerable Kerberos decrypt helper through the UDP RxRPC/RxGK RESPONSE path; Ceph and AFS also expose network-driven paths.\nAC:L - Once an async AEAD implementation is selected, each accepted operation can return -EINPROGRESS and trigger the UAF. The attacker controls and can repeatedly invoke the packet flow, enabling heap grooming and race amplification.\nPR:N - RxGK decrypts the attacker-supplied token before validating the ticket, nonce, or authenticator. Looking up an installed server key selects the cipher but does not authenticate the peer.\nUI:N - A listening service processes the challenge and malicious response automatically without any victim action.\nS:U - Exploitation compromises resources governed by the same host kernel security authority and does not inherently cross a VM, IOMMU, or equivalent boundary.\nC:H - The freed request contains transform, callback, context, IV, and scatterlist-related state that can be reclaimed or accessed asynchronously, supporting controlled kernel-memory disclosure.\nI:H - The backend can write through stale scatterlist pointers, while reclaimed callback and request fields can enable arbitrary memory corruption or control-flow hijacking.\nA:H - The async worker dereferences freed or zeroed request state, allowing a repeatable kernel oops or panic; the defect has also been directly observed as a KASAN slab use-after-free."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["crypto/krb5/krb5_api.c"], "versions": [{"version": "00244da40f7821b242c4612428d4192230dba27f", "lessThan": "ef6feb77e2d91761427c5b773edc9c97e1b706ad", "status": "affected", "versionType": "git"}, {"version": "00244da40f7821b242c4612428d4192230dba27f", "lessThan": "2b7bd6dccff14b8b632c5244f1fd506918077221", "status": "affected", "versionType": "git"}, {"version": "00244da40f7821b242c4612428d4192230dba27f", "lessThan": "6c9dddeb582fde005360f4fe02c760d45ca05fb5", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["crypto/krb5/krb5_api.c"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.4", "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": "6.15", "versionEndExcluding": "6.18.39"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.1.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad"}, {"url": "https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221"}, {"url": "https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5"}], "title": "crypto: krb5 - filter out async aead implementations at alloc", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["crypto/krb5/krb5_api.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "ef6feb77e2d91761427c5b773edc9c97e1b706ad", "status": "affected", "version": "00244da40f7821b242c4612428d4192230dba27f", "versionType": "git"}, {"lessThan": "2b7bd6dccff14b8b632c5244f1fd506918077221", "status": "affected", "version": "00244da40f7821b242c4612428d4192230dba27f", "versionType": "git"}, {"lessThan": "6c9dddeb582fde005360f4fe02c760d45ca05fb5", "status": "affected", "version": "00244da40f7821b242c4612428d4192230dba27f", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["crypto/krb5/krb5_api.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"lessThan": "6.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.39", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "1DA3E752-10DF-4260-A04E-FB6A07086768", "versionEndExcluding": "6.18.39", "versionStartIncluding": "6.15", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "6228DDD6-4557-4AA3-9F43-AB995D471E42", "versionEndExcluding": "7.1.4", "versionStartIncluding": "6.19", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: krb5 - filter out async aead implementations at alloc\n\nkrb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and\nrfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL\ncompletion callback and treat any negative return from\ncrypto_aead_{encrypt,decrypt}() as terminal, falling through to\nkfree_sensitive(buffer). When the encrypt_name resolves to an\nasync AEAD instance the request returns -EINPROGRESS, the buffer\nis freed while the backend's worker still holds a pointer, and the\nworker dereferences the freed slab on completion.\n\nKASAN report under UML+SLUB with a synthetic async aead backend\nbound to krb5->encrypt_name:\n\n BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7\n\nThe helpers were written synchronously, so filter the async\ninstances out at allocation time instead of plumbing\ncrypto_wait_req() through every call site.\n\nReachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and\nnet/ceph/crypto.c on systems with an async AEAD provider bound to\nthe krb5 enctype name."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ncrypto: krb5 - filtrar implementaciones AEAD as\u00edncronas en la asignaci\u00f3n\n\nkrb5_aead_encrypt(), krb5_aead_decrypt() en rfc3961_simplified.c y rfc8009_encrypt(), rfc8009_decrypt() en rfc8009_aes2.c establecen una devoluci\u00f3n de llamada de finalizaci\u00f3n NULL y tratan cualquier retorno negativo de crypto_aead_{encrypt,decrypt}() como terminal, pasando a kfree_sensitive(buffer). Cuando el encrypt_name se resuelve en una instancia AEAD as\u00edncrona, la solicitud devuelve -EINPROGRESS, el b\u00fafer es liberado mientras el trabajador del backend a\u00fan mantiene un puntero, y el trabajador desreferencia el slab liberado al finalizar.\n\nInforme KASAN bajo UML+SLUB con un backend AEAD as\u00edncrono sint\u00e9tico vinculado a krb5 -> encrypt_name:\n\nBUG: KASAN: uso despu\u00e9s de liberaci\u00f3n de slab en t5_stub_complete+0x7d/0xc7\n\nLos ayudantes fueron escritos de forma s\u00edncrona, as\u00ed que filtrar las instancias as\u00edncronas en el momento de la asignaci\u00f3n en lugar de pasar crypto_wait_req() a trav\u00e9s de cada sitio de llamada.\n\nAlcanzable a trav\u00e9s de net/rxrpc/rxgk.c, fs/afs/cm_security.c y net/ceph/crypto.c en sistemas con un proveedor AEAD as\u00edncrono vinculado al nombre de tipo de cifrado krb5."}], "id": "CVE-2026-64439", "lastModified": "2026-10-24T13:10:00.147", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-25T10:17:28.447", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: crypto: krb5 - filter out async aead implementations at alloc", "id": "2507234", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507234"}, "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-825", "details": ["A flaw was found in the Linux kernel's Kerberos 5 (krb5) cryptography module. This use-after-free vulnerability occurs when an asynchronous Authenticated Encryption with Associated Data (AEAD) instance is used. The system prematurely frees a memory buffer while a backend process still holds a pointer to it, leading to the process attempting to access the freed memory. This can result in a system crash, causing a Denial of Service (DoS)."], "name": "CVE-2026-64439", "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": "2026-07-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64439\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64439\nhttps://lore.kernel.org/linux-cve-announce/2026072538-CVE-2026-64439-5378@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[00244da40f7821b242c4612428d4192230dba27f,ef6feb77e2d91761427c5b773edc9c97e1b706ad)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[00244da40f7821b242c4612428d4192230dba27f,2b7bd6dccff14b8b632c5244f1fd506918077221)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[00244da40f7821b242c4612428d4192230dba27f,6c9dddeb582fde005360f4fe02c760d45ca05fb5)"}}], "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": "6.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.39,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.4,7.2.0)"}}, {"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": "2026-07-25T19:45:03.151120+00:00", "updated": "2026-09-03T20:30:10.433491+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-416", "CWE-825"]}