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CVE Record

CVE-2025-21699: gfs2: Truncate address space when flipping GFS2_DIF_JDATA flag

In the Linux kernel, the following vulnerability has been resolved: gfs2: Truncate address space when flipping GFS2_DIF_JDATA flag Truncate an inode's address space when flipping the GFS2_DIF_JDATA flag: depending on that flag, the pages in the address space will either use buffer heads or iomap_folio_state structs, and we cannot mix the two.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux GFS2 filesystem flaw can leave incompatible in-memory page metadata together after a journaling-data flag changes. Under the supplied CVSS assessment, a low-privileged local attacker could potentially compromise confidentiality, integrity, and availability. Only systems using the affected GFS2 path are likely exposed; the exact triggering conditions are not documented in the bundle.

Executive priority

Treat this as a high-priority infrastructure patch for GFS2 systems, especially multi-user or shared-storage hosts. It is less urgent for systems that do not use GFS2. No active exploitation is established, but the assessed impact is complete loss of confidentiality, integrity, and availability on a successfully exploited host.

Technical view

When GFS2_DIF_JDATA changes, cached pages may retain buffer-head metadata while subsequent handling expects iomap_folio_state, or vice versa. Mixing these representations is unsafe. The upstream correction truncates the inode address space during the transition. The bundle scores the issue CVSS 3.1 7.8: local, low complexity, low privileges, no user interaction, and high CIA impact.

Likely exposure

Prioritize Linux hosts that mount or actively use GFS2, particularly shared-storage cluster systems. Exposure also depends on running an affected kernel and reaching the flag-transition path. The supplied version data is ambiguous and should not be treated as authoritative fixed-version boundaries; confirm package status with the distribution vendor.

Exploitation context

The supplied record requires local access and low privileges rather than network access. It is not listed in CISA KEV, and the bundle provides no evidence of public or active exploitation. Precise prerequisites beyond the GFS2 code path are incomplete.

Researcher notes

The core invariant is that an inode address space must not contain pages initialized under both GFS2 metadata representations. The fix invalidates that address space when GFS2_DIF_JDATA flips. The bundle does not identify a CWE, proof of concept, observed attacks, crash signature, or exact fixed package matrix. Avoid inferring exploitability beyond the supplied local CVSS vector.

Mitigation direction

  • Install a vendor-supported kernel update that incorporates the applicable referenced GFS2 stable fix.
  • Reboot into the updated kernel; installing a package alone may leave the vulnerable kernel running.
  • Consult distribution advisories for package-specific fixed versions because the supplied version boundaries are ambiguous.
  • Where immediate updating is impossible, reduce untrusted local access to affected GFS2 hosts pending vendor guidance.

Validation and detection

  • Inventory mounted filesystem types and identify hosts using GFS2.
  • Record each host's running kernel version, not merely its installed kernel packages.
  • Map distribution package builds to vendor advisories or confirm inclusion of the applicable stable commit.
  • After updating and rebooting, verify the running kernel matches the vendor-fixed package.
  • Regression-test normal GFS2 workloads and cluster filesystem operations after remediation.
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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2025-21699 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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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.

2CVSS vectors
3Timeline events
2ADP providers
10Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

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
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-21699Attack 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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux2164f9b9186962ffb7c687e18ec6f5255525f09d, 2164f9b9186962ffb7c687e18ec6f5255525f09d, 2164f9b9186962ffb7c687e18ec6f5255525f09d, 2164f9b9186962ffb7c687e18ec6f5255525f09d, 2164f9b9186962ffb7c687e18ec6f5255525f09d, 2164f9b9186962ffb7c687e18ec6f5255525f09d, 2164f9b9186962ffb7c687e18ec6f5255525f09dunaffected
LinuxLinux5.10, 0, 5.10.234, 5.15.178, 6.1.128, 6.6.75, 6.12.12, 6.13.1, 6.14affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.