Vulnerability-Lookup

GHSA-V7VW-MGW4-JQVJ

Vulnerability from github – Published: 2025-07-10 09:32 – Updated: 2025-11-18 15:30

Details

In the Linux kernel, the following vulnerability has been resolved:

smb: Log an error when close_all_cached_dirs fails

Under low-memory conditions, close_all_cached_dirs() can't move the dentries to a separate list to dput() them once the locks are dropped. This will result in a "Dentry still in use" error, so add an error message that makes it clear this is what happened:

[ 495.281119] CIFS: VFS: \otters.example.com\share Out of memory while dropping dentries [ 495.281595] ------------[ cut here ]------------ [ 495.281887] BUG: Dentry ffff888115531138{i=78,n=/} still in use (2) [unmount of cifs cifs] [ 495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0

Also, bail out of looping through all tcons as soon as a single allocation fails, since we're already in trouble, and kmalloc() attempts for subseqeuent tcons are likely to fail just like the first one did.

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-38321"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-07-10T09:15:26Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: Log an error when close_all_cached_dirs fails\n\nUnder low-memory conditions, close_all_cached_dirs() can\u0027t move the\ndentries to a separate list to dput() them once the locks are dropped.\nThis will result in a \"Dentry still in use\" error, so add an error\nmessage that makes it clear this is what happened:\n\n[  495.281119] CIFS: VFS: \\\\otters.example.com\\share Out of memory while dropping dentries\n[  495.281595] ------------[ cut here ]------------\n[  495.281887] BUG: Dentry ffff888115531138{i=78,n=/}  still in use (2) [unmount of cifs cifs]\n[  495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0\n\nAlso, bail out of looping through all tcons as soon as a single\nallocation fails, since we\u0027re already in trouble, and kmalloc() attempts\nfor subseqeuent tcons are likely to fail just like the first one did.",
  "id": "GHSA-v7vw-mgw4-jqvj",
  "modified": "2025-11-18T15:30:40Z",
  "published": "2025-07-10T09:32:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38321"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43f26094d6702e494e800532c3f1606e7a68eb30"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4479db143390bdcadc1561292aab579cdfa9f6c6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a2182743a8b4969481f64aec4908ff162e8a206c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b8ced2b9a23a1a2c1e0ed8d0d02512e51bdf38da"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-38321 (GCVE-0-2025-38321)

Vulnerability from cvelistv5 – Published: 2025-07-10 08:14 – Updated: 2026-10-15 21:52

Title

smb: Log an error when close_all_cached_dirs fails

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: Log an error when close_all_cached_dirs fails Under low-memory conditions, close_all_cached_dirs() can't move the dentries to a separate list to dput() them once the locks are dropped. This will result in a "Dentry still in use" error, so add an error message that makes it clear this is what happened: [ 495.281119] CIFS: VFS: \\otters.example.com\share Out of memory while dropping dentries [ 495.281595] ------------[ cut here ]------------ [ 495.281887] BUG: Dentry ffff888115531138{i=78,n=/} still in use (2) [unmount of cifs cifs] [ 495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0 Also, bail out of looping through all tcons as soon as a single allocation fails, since we're already in trouble, and kmalloc() attempts for subseqeuent tcons are likely to fail just like the first one did.

Severity

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 2026-10-15 21:49 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7018 records in the last 180 days details

References

4 references

URL	Tags
https://git.kernel.org/stable/c/b8ced2b9a23a1a2c1…
https://git.kernel.org/stable/c/43f26094d6702e494…
https://git.kernel.org/stable/c/4479db143390bdcad…
https://git.kernel.org/stable/c/a2182743a8b496948…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 73934e535cffbda1490fa97d82690a0f9aa73e94 , < b8ced2b9a23a1a2c1e0ed8d0d02512e51bdf38da (git) Affected: 548812afd96982a76a93ba76c0582ea670c40d9e , < 43f26094d6702e494e800532c3f1606e7a68eb30 (git) Affected: 3fa640d035e5ae526769615c35cb9ed4be6e3662 , < 4479db143390bdcadc1561292aab579cdfa9f6c6 (git) Affected: 3fa640d035e5ae526769615c35cb9ed4be6e3662 , < a2182743a8b4969481f64aec4908ff162e8a206c (git) Affected: ff4528bbc82d0d90073751f7b49e7b9e9c7e5638 (git) Affected: 6.6.64 , < 6.6.95 (semver) Affected: 6.12.2 , < 6.12.35 (semver) Affected: 6.11.11 , < 6.12 (semver)
Linux	Linux	Affected: 6.13 Unaffected: 0 , < 6.13 (semver) Unaffected: 6.6.95 , ≤ 6.6.* (semver) Unaffected: 6.12.35 , ≤ 6.12.* (semver) Unaffected: 6.15.4 , ≤ 6.15.* (semver) Unaffected: 6.16 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-38321",
                "options": [
                  {
                    "Exploitation": "none"
                  },
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-15T21:49:37.462417Z",
                "version": "2.0.3"
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              "type": "ssvc"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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            },
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              "status": "affected",
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              "version": "6.12.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
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          "nodes": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: Log an error when close_all_cached_dirs fails\n\nUnder low-memory conditions, close_all_cached_dirs() can\u0027t move the\ndentries to a separate list to dput() them once the locks are dropped.\nThis will result in a \"Dentry still in use\" error, so add an error\nmessage that makes it clear this is what happened:\n\n[  495.281119] CIFS: VFS: \\\\otters.example.com\\share Out of memory while dropping dentries\n[  495.281595] ------------[ cut here ]------------\n[  495.281887] BUG: Dentry ffff888115531138{i=78,n=/}  still in use (2) [unmount of cifs cifs]\n[  495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0\n\nAlso, bail out of looping through all tcons as soon as a single\nallocation fails, since we\u0027re already in trouble, and kmalloc() attempts\nfor subseqeuent tcons are likely to fail just like the first one did."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable code runs only in `cifs_kill_sb()` on the local unmount path, and the triggering condition is a local GFP_ATOMIC allocation failure under memory pressure; a remote SMB server can influence how many cached dirs exist but cannot drive the unmount or the OOM.\nAC:L - Memory pressure is directly attacker-inducible and GFP_ATOMIC allocations fail readily under it, and the mount/unmount cycle can be repeated indefinitely, with up to `max_cached_dirs` allocations per tcon per unmount (multiplied further by `multiuser` mounts) giving many independent chances to hit the failure.\nPR:L - A basic unprivileged local account suffices to create the memory pressure, and the unmount is reachable to the same user through the standard `user`/`users` fstab option for SMB shares, setuid `mount.cifs`, or an autofs/systemd idle-expiry unmount; no root or CAP_SYS_ADMIN in the init namespace is required.\nUI:N - On user-mountable shares the attacker performs the mount, the memory exhaustion, and the unmount entirely from their own process, and on automounted shares the expiry unmount happens on a timer with no victim action at all.\nS:U - The leaked dentries, poisoned inodes, and freed superblock are all kernel objects within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - When the tcon is shared with a surviving superblock, the undropped `cfid-\u003edentry` outlives `destroy_super()`, so the later `dput()` reads `dentry-\u003ed_sb` fields (`s_dentry_lru`, `s_d_op`, `s_type`) out of a freed kmalloc-2k object the attacker can reoccupy, giving a use-after-free read primitive over sprayed heap contents.\nI:H - The same dangling `dput()` performs list operations on the freed superblock\u0027s `s_dentry_lru`, writing into attacker-groomed heap memory, and the VFS additionally overwrites `i_op`/`i_sb`/`i_mapping` of the still-referenced inodes \u2014 a use-after-free write primitive usable for control-flow corruption.\nA:H - The failure deterministically produces `WARN(1, \"BUG: Dentry ... still in use\")` in `umount_check()` (a panic under `panic_on_warn`), then `CHECK_DATA_CORRUPTION()` on busy inodes which is an outright `BUG()` with `CONFIG_BUG_ON_DATA_CORRUPTION=y`, and otherwise poisons the inodes so the subsequent `iput_final()` oopses on `VFS_PTR_POISON`."
            }
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        {
          "url": "https://git.kernel.org/stable/c/a2182743a8b4969481f64aec4908ff162e8a206c"
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      "title": "smb: Log an error when close_all_cached_dirs fails",
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    "cveId": "CVE-2025-38321",
    "datePublished": "2025-07-10T08:14:57.046Z",
    "dateReserved": "2025-04-16T04:51:24.004Z",
    "dateUpdated": "2026-10-15T21:52:14.275Z",
    "state": "PUBLISHED"
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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.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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