{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38561", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.025Z", "datePublished": "2025-08-19T17:02:38.719Z", "dateUpdated": "2026-08-05T12:02:55.275Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:02:55.275Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix Preauh_HashValue race condition\n\nIf client send multiple session setup requests to ksmbd,\nPreauh_HashValue race condition could happen.\nThere is no need to free sess->Preauh_HashValue at session setup phase.\nIt can be freed together with session at connection termination phase." } ], "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 - ksmbd is the in-kernel SMB server listening on TCP/445, and the entire path is driven by remote SMB2 SESSION_SETUP PDUs parsed straight off the socket. Internet- and LAN-facing NAS, container, and file-server deployments are directly exposed.\nAC:L - The attacker controls both sides of the race completely — how many SESSION_SETUP PDUs to pipeline, across how many TCP connections, whether to use multichannel binding to bypass the per-connection mutex entirely, and when to drop the socket to race connection teardown. ksmbd's non-ordered workqueue guarantees parallel processing, and failed attempts cost only a reconnect.\nPR:N - SESSION_SETUP is the authentication handshake itself; the buffer is allocated, hashed, and read on the response path before any credential is verified, and the NtLmNegotiate racer is fully pre-authentication. The guest branch of ntlm_authenticate() skips the NTLM blob check entirely, reaching the vulnerable kfree() with no credentials on the common guest-mapped share configuration.\nUI:N - Exploitation requires only that the attacker connect to the SMB port and send session setup requests. No action by any local user or administrator is needed.\nS:U - The double free and use-after-free corrupt kernel heap memory within the kernel's own security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed 64-byte chunk is read back via sha512_update() and, decisively, serves as the KDF context for the SMB 3.1.1 signing and encryption keys — reclaiming it with chosen content yields attacker-known session keys and decryption of other clients' traffic. The double free of a general-purpose kmalloc-64 object is also a standard route to a full arbitrary-read primitive.\nI:H - This is a double free of a kmalloc-64 object plus a 64-byte out-of-lifetime write (sha512_final into the freed buffer) that clobbers whatever victim object reclaimed the slot, giving the classic heap-grooming path to arbitrary write and control-flow hijack. It additionally enables forging signed SMB messages by controlling the signing-key derivation context.\nA:H - The double free corrupts the SLUB freelist and the use-after-free write smashes reclaimed objects, both of which panic the kernel. The racing NULL store also reaches ksmbd_gen_smb311_encryptionkey()/ksmbd_gen_smb311_signingkey(), which dereference sess->Preauth_HashValue with no NULL check, for a trivially repeatable remote oops." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "fbf5c0845ed15122a770bca9be1d9b60b470d3aa", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "b69fd87076daa66f3d186bd421a7b0ee0cb45829", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "edeecc7871e8fc0878d53ce286c75040a0e38f6c", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "7d7c0c5304c88bcbd7a85e9bcd61d27e998ba5fc", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "6613887da1d18dd2ecfd6c6148a873c4d903ebdc", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "44a3059c4c8cc635a1fb2afd692d0730ca1ba4b6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.148", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.102", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.42", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.10", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.1", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "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": "5.15", "versionEndExcluding": "6.1.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.102" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.15.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.16.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fbf5c0845ed15122a770bca9be1d9b60b470d3aa" }, { "url": "https://git.kernel.org/stable/c/b69fd87076daa66f3d186bd421a7b0ee0cb45829" }, { "url": "https://git.kernel.org/stable/c/edeecc7871e8fc0878d53ce286c75040a0e38f6c" }, { "url": "https://git.kernel.org/stable/c/7d7c0c5304c88bcbd7a85e9bcd61d27e998ba5fc" }, { "url": "https://git.kernel.org/stable/c/6613887da1d18dd2ecfd6c6148a873c4d903ebdc" }, { "url": "https://git.kernel.org/stable/c/44a3059c4c8cc635a1fb2afd692d0730ca1ba4b6" }, { "url": "https://www.zerodayinitiative.com/advisories/ZDI-25-916/" } ], "title": "ksmbd: fix Preauh_HashValue race condition", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "CHANGED", "version": "3.1", "baseScore": 8.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2025-38561", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-09-26T03:55:12.286714Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-362", "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-02-26T17:48:28.579Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:39:50.588Z" } } ] } }