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CVE Record

CVE-2023-54140: nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse A syzbot stress test using a corrupted disk image reported that mark_buffer_dirty() called from __nilfs_mark_inode_dirty() or nilfs_palloc_commit_alloc_entry() may output a kernel warning, and can panic if the kernel is booted with panic_on_warn. This is because nilfs2 keeps buffer pointers in local structures for some metadata and reuses them, but such buffers may be forcibly discarded by nilfs_clear_dirty_page() in some critical situations. This issue is reported to appear after commit 28a65b49eb53 ("nilfs2: do not write dirty data after degenerating to read-only"), but the issue has potentially existed before. Fix this issue by checking the uptodate flag when attempting to reuse an internally held buffer, and reloading the metadata instead of reusing the buffer if the flag was lost.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in Linux’s NILFS2 filesystem can reuse invalidated metadata buffers when processing a corrupted filesystem. This may trigger a kernel warning and, on systems configured to panic on warnings, crash the operating system. The CVSS assessment also indicates possible confidentiality and integrity impact, although the supplied description demonstrates only warnings and potential panic.

Executive priority

Treat this as a focused high-priority kernel maintenance issue, not an internet-wide emergency. Expedite remediation for hosts using NILFS2 or processing untrusted filesystem images, especially systems configured to panic on warnings. Other Linux hosts should follow normal vendor patch cycles after confirming whether their packaged kernels contain affected code.

Technical view

NILFS2 retains metadata buffer pointers in local structures. Under critical conditions, nilfs_clear_dirty_page() can discard those buffers, yet allocation or inode-dirtying paths may reuse them. The fix checks whether a retained buffer remains up to date and reloads its metadata when necessary. A syzbot stress test using a corrupted disk image exposed the condition.

Likely exposure

Exposure is limited to Linux systems using affected NILFS2 code and processing a filesystem capable of triggering the discarded-buffer condition. Risk is higher where untrusted or corrupted NILFS2 images may be handled or panic_on_warn is enabled. The supplied affected-version data is ambiguous, so kernel and distribution advisories should determine exact exposure.

Exploitation context

The CVSS vector describes a local, low-complexity issue requiring low privileges and no user interaction. The bundle documents discovery through syzbot with a corrupted disk image. It does not establish practical privilege escalation, public weaponization, or active exploitation, and the CVE is not listed as KEV.

Researcher notes

The demonstrated path involves stale NILFS2 metadata-buffer reuse after a buffer loses its uptodate state. Referenced commits appear to carry the correction across stable branches. The supplied version lists contain duplicate commit identifiers and unclear boundaries; do not infer exact vulnerable ranges without distribution mapping. Impact beyond warning or panic is asserted by CVSS but not demonstrated in the description.

Mitigation direction

  • Update to a vendor-supported kernel containing the applicable upstream NILFS2 stable fix.
  • Consult the Linux distribution’s advisory to map the fix to its packaged kernel versions.
  • Prioritize systems that use NILFS2, accept filesystem images, or enable panic_on_warn.
  • Restrict handling of untrusted NILFS2 media until the corrected kernel is installed.

Validation and detection

  • Inventory running kernel versions and identify systems with NILFS2 configured, loaded, or mounted.
  • Compare each packaged kernel against its distribution advisory and the referenced stable fix commits.
  • Confirm the replacement kernel is active after updating, not merely installed.
  • Review kernel logs for NILFS2-related mark_buffer_dirty warnings or unexpected warning-triggered panics.
  • Test filesystem handling safely in an isolated environment without using production data.
Prepared
Confidence
medium
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2023-54140 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
10Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2023-54140Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40c, 8c26c4e2694a163d525976e804d81cd955bbb40cunaffected
LinuxLinux3.10, 0, 4.14.326, 4.19.295, 5.4.257, 5.10.195, 5.15.131, 6.1.52, 6.4.15, 6.5.2, 6.6affected
Weakness

CWE details

No CWE listed

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