CVE-2026-64439

In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - filter out async aead implementations at alloc krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer). When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion. KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name: BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7 The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site. Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221	Patch
https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5	Patch
https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::

History

No history.

Information

Published : 2026-07-25 10:17

Updated : 2026-09-03 17:50

NVD link : CVE-2026-64439

Mitre link : CVE-2026-64439

CVE.ORG link : CVE-2026-64439

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-416

Use After Free

{"id": "CVE-2026-64439", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "00244da40f7821b242c4612428d4192230dba27f", "lessThan": "ef6feb77e2d91761427c5b773edc9c97e1b706ad", "versionType": "git"}, {"status": "affected", "version": "00244da40f7821b242c4612428d4192230dba27f", "lessThan": "2b7bd6dccff14b8b632c5244f1fd506918077221", "versionType": "git"}, {"status": "affected", "version": "00244da40f7821b242c4612428d4192230dba27f", "lessThan": "6c9dddeb582fde005360f4fe02c760d45ca05fb5", "versionType": "git"}], "programFiles": ["crypto/krb5/krb5_api.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"status": "unaffected", "version": "0", "lessThan": "6.15", "versionType": "semver"}, {"status": "unaffected", "version": "6.18.39", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.1.4", "versionType": "semver", "lessThanOrEqual": "7.1.*"}, {"status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["crypto/krb5/krb5_api.c"], "defaultStatus": "affected"}]}], "published": "2026-07-25T10:17:28.447", "references": [{"url": "https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-416"}]}], "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."}], "lastModified": "2026-09-03T17:50:14.653", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1DA3E752-10DF-4260-A04E-FB6A07086768", "versionEndExcluding": "6.18.39", "versionStartIncluding": "6.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "6228DDD6-4557-4AA3-9F43-AB995D471E42", "versionEndExcluding": "7.1.4", "versionStartIncluding": "6.19"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}