CVE-2026-53040

HIGHPre-NVD 7.17.1—
EchelonGraph scoreHIGH confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-06-24. a secondary CVSS source baseline 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

ocfs2: validate bg_bits during freefrag scan

[BUG] A crafted filesystem can trigger an out-of-bounds bitmap walk when OCFS2_IOC_INFO is issued with OCFS2_INFO_FL_NON_COHERENT.

BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: use-after-free in test_bit_le include/asm-generic/bitops/le.h:21 [inline] BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline] BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline] BUG: KASAN: use-after-free in ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline] BUG: KASAN: use-after-free in ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754 Read of size 8 at addr ffff888031bce000 by task syz.0.636/1435 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xd1/0x650 mm/kasan/report.c:482 kasan_report+0xfb/0x140 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x11c/0x200 mm/kasan/generic.c:200 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] test_bit_le include/asm-generic/bitops/le.h:21 [inline] ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline] ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline] ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline] ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754 ocfs2_info_handle+0x18d/0x2a0 fs/ocfs2/ioctl.c:828 ocfs2_ioctl+0x632/0x6e0 fs/ocfs2/ioctl.c:913 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583 ...

[CAUSE] ocfs2_info_freefrag_scan_chain() uses on-disk bg_bits directly as the bitmap scan limit. The coherent path reads group descriptors through ocfs2_read_group_descriptor(), which validates the descriptor before use. The non-coherent path uses ocfs2_read_blocks_sync() instead and skips that validation, so an impossible bg_bits value can drive the bitmap walk past the end of the block.

[FIX] Compute the bitmap capacity from the filesystem format with ocfs2_group_bitmap_size(), report descriptors whose bg_bits exceeds that limit, and clamp the scan to the computed capacity. This keeps the freefrag report going while avoiding reads beyond the buffer.

CVSS v3
7.1
EG Score
7.1(high)
EPSS
2.3%
KEV
Not listed

Published

June 24, 2026

Last Modified

June 28, 2026

Advisory Details (8)

Auto-updated Jun 30, 2026
No patch confirmed yet.
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e0dcf12665d6dde37facf790803cdad44d5c328c
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bb3c54d1e71578521111f1a1ee7d5f4761a242b8
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bb2906a1065ec28de021bac2ed03f2624edd7d07
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8f687eeed3da3012152b0f9473f578869de0cd7b
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4c2d62ddde8928db12f4608950b67a20e67deab2
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3e167e230d19cd273108bab2e4c61800fc335ae8
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0998674eec138c55e9e349b9cbd9dbc5129a9cc8
generic

ocfs2: validate bg_bits during freefrag scan - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e

Vendor Advisories for CVE-2026-53040(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 36× in last 7d / 48× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-07 00:38 UTCEG score recompute
  2. 2026-07-07 00:38 UTCGHSA enrichment
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 13:20 UTCEG score recompute
  6. 2026-07-06 13:20 UTCGHSA enrichment
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-06 02:23 UTCEPSS rescore
  9. 2026-07-06 01:38 UTCEG score recompute
  10. 2026-07-06 01:38 UTCGHSA enrichment
  11. 2026-07-05 14:20 UTCEG score recompute
  12. 2026-07-05 14:20 UTCGHSA enrichment
  13. 2026-07-05 03:00 UTCEG score recompute
  14. 2026-07-05 03:00 UTCGHSA enrichment
  15. 2026-07-05 02:31 UTCEPSS rescore
  16. 2026-07-05 02:30 UTCEPSS rescore
  17. 2026-07-04 15:43 UTCEG score recompute
  18. 2026-07-04 15:42 UTCGHSA enrichment
  19. 2026-07-04 06:31 UTCEPSS rescore
  20. 2026-07-04 04:23 UTCEG score recompute
  21. 2026-07-04 04:23 UTCGHSA enrichment
  22. 2026-07-03 17:02 UTCEG score recompute
  23. 2026-07-03 17:02 UTCGHSA enrichment
  24. 2026-07-03 05:44 UTCEG score recompute
  25. 2026-07-03 05:44 UTCGHSA enrichment
Show 23 more
  1. 2026-07-02 18:25 UTCEG score recompute
  2. 2026-07-02 18:25 UTCGHSA enrichment
  3. 2026-07-02 07:07 UTCEG score recompute
  4. 2026-07-02 07:07 UTCGHSA enrichment
  5. 2026-07-01 19:48 UTCEG score recompute
  6. 2026-07-01 19:48 UTCGHSA enrichment
  7. 2026-07-01 08:31 UTCEG score recompute
  8. 2026-07-01 08:31 UTCGHSA enrichment
  9. 2026-06-30 23:22 UTCEPSS rescore
  10. 2026-06-30 21:13 UTCEG score recompute▲ 7.10
  11. 2026-06-30 21:13 UTCGHSA enrichment
  12. 2026-06-29 14:06 UTCEPSS rescore
  13. 2026-06-29 14:06 UTCEPSS rescore
  14. 2026-06-28 14:07 UTCEPSS rescore
  15. 2026-06-28 07:52 UTCMITRE cvelistV5CVSS v3 → 7.1 · severity → HIGH
  16. 2026-06-28 04:56 UTCEPSS rescore
  17. 2026-06-28 04:56 UTCEPSS rescore
  18. 2026-06-27 19:45 UTCEG score recompute
  19. 2026-06-27 19:44 UTCGHSA enrichment
  20. 2026-06-27 03:08 UTCEPSS rescore
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-24 18:18 UTCEG score recompute
  23. 2026-06-24 18:03 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-53040?
CVE-2026-53040 is a high vulnerability published on June 24, 2026. In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate bg_bits during freefrag scan [BUG] A crafted filesystem can trigger an out-of-bounds bitmap walk when OCFS2IOCINFO is issued with OCFS2INFOFLNONCOHERENT. BUG: KASAN: use-after-free in instrumentatomicread…
When was CVE-2026-53040 disclosed?
CVE-2026-53040 was first published in the National Vulnerability Database on June 24, 2026, with the most recent update on June 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53040 actively exploited?
CVE-2026-53040 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53040?
CVE-2026-53040 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-53040?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53040, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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