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CVE-2025-21945 (GCVE-0-2025-21945)

Vulnerability from cvelistv5 – Published: 2025-04-01 15:41 – Updated: 2026-08-05 11:55
VLAI
Title
ksmbd: fix use-after-free in smb2_lock
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in smb2_lock If smb_lock->zero_len has value, ->llist of smb_lock is not delete and flock is old one. It will cause use-after-free on error handling routine.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-04-16 13:14 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 410ce35a2ed6d0e114132bba29af49b69880c8c7 (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 8573571060ca466cbef2c6f03306b2cc7b883506 (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < a0609097fd10d618aed4864038393dd75131289e (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 636e021646cf9b52ddfea7c809b018e91f2188cb (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 84d2d1641b71dec326e8736a749b7ee76a9599fc (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.1.131 , ≤ 6.1.* (semver)
Unaffected: 6.6.83 , ≤ 6.6.* (semver)
Unaffected: 6.12.19 , ≤ 6.12.* (semver)
Unaffected: 6.13.7 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-28T02:02:39Z",
      "cve": "CVE-2025-21945",
      "id": "CVE-2025-21945",
      "initial_release_date": "2025-04-04T02:58:52Z",
      "product_status:known_not_affected": "457",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-21945",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-21945.json",
      "version": "10"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2025-11-03T19:39:45.983Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.8, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2025-21945\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-04-16T13:14:55.516245Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-416\", \"description\": \"CWE-416 Use After Free\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-04-16T13:14:56.950Z\"}}], \"cna\": {\"title\": \"ksmbd: fix use-after-free in smb2_lock\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 8.8, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:N - ksmbd is the in-kernel SMB server listening on TCP/445, and the entire bug is triggered by a single crafted SMB2 LOCK PDU whose lock elements carry Length==0 and attacker-chosen flags. No local access to the target is needed.\\nAC:L - The zero_len path is taken deterministically whenever the client sets a lock element\u0027s Length to 0, and the stale `flock`/`flags` reuse and skipped `list_del` follow unconditionally; there is no race and the attacker can repeat the request indefinitely to groom the heap.\\nPR:L - SMB2_LOCK is gated by smb2_check_user_session() and requires an open file handle from ksmbd_lookup_fd_slow(), so the attacker needs valid credentials for an exported share \\u2014 an ordinary low-privileged SMB account, not administrative rights.\\nUI:N - The attacker drives the whole sequence (session setup, tree connect, create, lock) from its own connection; no action by any local user or administrator is required.\\nS:U - The corruption is confined to kernel heap objects managed by the SMB server and the VFS lock layer, within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\\nC:H - The freed ksmbd_lock stays linked in lock_list and in the global per-connection lock_list, and the stale file_lock is re-read by vfs_lock_file() and by other connections\u0027 conflict scans, so reclaimed heap contents are dereferenced and can be leveraged to disclose kernel memory.\\nI:H - The dangling entries produce a double-free plus list_del writes through attacker-groomable freed slab objects, giving the write primitives needed to corrupt adjacent kernel structures and hijack control flow.\\nA:H - Use of freed ksmbd_lock/file_lock memory and the resulting double-free and corrupted list traversals reliably oops or panic the kernel, taking down the whole file server.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"0626e6641f6b467447c81dd7678a69c66f7746cf\", \"lessThan\": \"410ce35a2ed6d0e114132bba29af49b69880c8c7\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"0626e6641f6b467447c81dd7678a69c66f7746cf\", \"lessThan\": \"8573571060ca466cbef2c6f03306b2cc7b883506\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"0626e6641f6b467447c81dd7678a69c66f7746cf\", \"lessThan\": \"a0609097fd10d618aed4864038393dd75131289e\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"0626e6641f6b467447c81dd7678a69c66f7746cf\", \"lessThan\": \"636e021646cf9b52ddfea7c809b018e91f2188cb\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"0626e6641f6b467447c81dd7678a69c66f7746cf\", \"lessThan\": \"84d2d1641b71dec326e8736a749b7ee76a9599fc\", \"versionType\": \"git\"}], \"programFiles\": [\"fs/smb/server/smb2pdu.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.15\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.15\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"6.1.131\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.83\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.19\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.13.7\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.13.*\"}, {\"status\": \"unaffected\", \"version\": \"6.14\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"fs/smb/server/smb2pdu.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/410ce35a2ed6d0e114132bba29af49b69880c8c7\"}, {\"url\": \"https://git.kernel.org/stable/c/8573571060ca466cbef2c6f03306b2cc7b883506\"}, {\"url\": \"https://git.kernel.org/stable/c/a0609097fd10d618aed4864038393dd75131289e\"}, {\"url\": \"https://git.kernel.org/stable/c/636e021646cf9b52ddfea7c809b018e91f2188cb\"}, {\"url\": \"https://git.kernel.org/stable/c/84d2d1641b71dec326e8736a749b7ee76a9599fc\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nksmbd: fix use-after-free in smb2_lock\\n\\nIf smb_lock-\u003ezero_len has value, -\u003ellist of smb_lock is not delete and\\nflock is old one. It will cause use-after-free on error handling\\nroutine.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.131\", \"versionStartIncluding\": \"5.15\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.83\", \"versionStartIncluding\": \"5.15\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.19\", \"versionStartIncluding\": \"5.15\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.13.7\", \"versionStartIncluding\": \"5.15\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.14\", \"versionStartIncluding\": \"5.15\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T11:55:30.419Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-21945\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T11:55:30.419Z\", \"dateReserved\": \"2024-12-29T08:45:45.790Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-04-01T15:41:08.471Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.