# CVE-2025-38337: jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata()

Status: published. Published: 2025-07-10. Updated: 2026-11-05.

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

jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata()

Since handle->h_transaction may be a NULL pointer, so we should change it
to call is_handle_aborted(handle) first before dereferencing it.

And the following data-race was reported in my fuzzer:

==================================================================
BUG: KCSAN: data-race in jbd2_journal_dirty_metadata / jbd2_journal_dirty_metadata

write to 0xffff888011024104 of 4 bytes by task 10881 on cpu 1:
 jbd2_journal_dirty_metadata+0x2a5/0x770 fs/jbd2/transaction.c:1556
 __ext4_handle_dirty_metadata+0xe7/0x4b0 fs/ext4/ext4_jbd2.c:358
 ext4_do_update_inode fs/ext4/inode.c:5220 [inline]
 ext4_mark_iloc_dirty+0x32c/0xd50 fs/ext4/inode.c:5869
 __ext4_mark_inode_dirty+0xe1/0x450 fs/ext4/inode.c:6074
 ext4_dirty_inode+0x98/0xc0 fs/ext4/inode.c:6103
....

read to 0xffff888011024104 of 4 bytes by task 10880 on cpu 0:
 jbd2_journal_dirty_metadata+0xf2/0x770 fs/jbd2/transaction.c:1512
 __ext4_handle_dirty_metadata+0xe7/0x4b0 fs/ext4/ext4_jbd2.c:358
 ext4_do_update_inode fs/ext4/inode.c:5220 [inline]
 ext4_mark_iloc_dirty+0x32c/0xd50 fs/ext4/inode.c:5869
 __ext4_mark_inode_dirty+0xe1/0x450 fs/ext4/inode.c:6074
 ext4_dirty_inode+0x98/0xc0 fs/ext4/inode.c:6103
....

value changed: 0x00000000 -> 0x00000001
==================================================================

This issue is caused by missing data-race annotation for jh->b_modified.
Therefore, the missing annotation needs to be added.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < 5c1a34ff5b0bfdfd2f9343aa9b08d25df618bac5 (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < ec669e5bf409f16e464bfad75f0ba039a45de29a (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < 43d5e3bb5f1dcd91e30238ea0b59a5f77063f84e (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < 23361b479f2700c00960d3ae9cdc8ededa762d47 (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < 2e7c64d7a92c031d016f11c8e8cb05131ab7b75a (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < f78b38af3540b4875147b7b884ee11a27b3dbf4c (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < a377996d714afb8d4d5f4906336f78510039da29 (affected, git); ≥ 6e06ae88edae77379bef7c0cb7d3c2dd88676867; < af98b0157adf6504fade79b3e6cb260c4ff68e37 (affected, git). Source: CNA: Linux
- Linux / Linux: 4.3 (affected); ≥ 0; < 4.3 (unaffected, semver); ≥ 5.4.295; ≤ 5.4.* (unaffected, semver); ≥ 5.10.239; ≤ 5.10.* (unaffected, semver); ≥ 5.15.186; ≤ 5.15.* (unaffected, semver); ≥ 6.1.142; ≤ 6.1.* (unaffected, semver); ≥ 6.6.95; ≤ 6.6.* (unaffected, semver); ≥ 6.12.35; ≤ 6.12.* (unaffected, semver); ≥ 6.15.4; ≤ 6.15.* (unaffected, semver); ≥ 6.16; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.20% as of 2026-11-05; percentile 9.35%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/5c1a34ff5b0bfdfd2f9343aa9b08d25df618bac5 (CNA: Linux)

- https://git.kernel.org/stable/c/ec669e5bf409f16e464bfad75f0ba039a45de29a (CNA: Linux)

- https://git.kernel.org/stable/c/43d5e3bb5f1dcd91e30238ea0b59a5f77063f84e (CNA: Linux)

- https://git.kernel.org/stable/c/23361b479f2700c00960d3ae9cdc8ededa762d47 (CNA: Linux)

- https://git.kernel.org/stable/c/2e7c64d7a92c031d016f11c8e8cb05131ab7b75a (CNA: Linux)

- https://git.kernel.org/stable/c/f78b38af3540b4875147b7b884ee11a27b3dbf4c (CNA: Linux)

- https://git.kernel.org/stable/c/a377996d714afb8d4d5f4906336f78510039da29 (CNA: Linux)

- https://git.kernel.org/stable/c/af98b0157adf6504fade79b3e6cb260c4ff68e37 (CNA: Linux)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (ADP: CVE)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html (ADP: CVE)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2025-38337; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-38337; retrieved 2026-11-05; source updated Not reported

Revision: 4081e02022163d2ce1f5e5c3d0699e02ca1e07d41ded7188954f020a961537c5

Canonical: https://y2.dev/cve/CVE-2025-38337

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.