CVE-2025-39779

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-09-11. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

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

btrfs: subpage: keep TOWRITE tag until folio is cleaned

btrfs_subpage_set_writeback() calls folio_start_writeback() the first time a folio is written back, and it also clears the PAGECACHE_TAG_TOWRITE tag even if there are still dirty blocks in the folio. This can break ordering guarantees, such as those required by btrfs_wait_ordered_extents().

That ordering breakage leads to a real failure. For example, running generic/464 on a zoned setup will hit the following ASSERT. This happens because the broken ordering fails to flush existing dirty pages before the file size is truncated.

assertion failed: !list_empty(&ordered->list) :: 0, in fs/btrfs/zoned.c:1899 ------------[ cut here ]------------ kernel BUG at fs/btrfs/zoned.c:1899! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 1906169 Comm: kworker/u130:2 Kdump: loaded Not tainted 6.16.0-rc6-BTRFS-ZNS+ #554 PREEMPT(voluntary) Hardware name: Supermicro Super Server/H12SSL-NT, BIOS 2.0 02/22/2021 Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] RIP: 0010:btrfs_finish_ordered_zoned.cold+0x50/0x52 [btrfs] RSP: 0018:ffffc9002efdbd60 EFLAGS: 00010246 RAX: 000000000000004c RBX: ffff88811923c4e0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff827e38b1 RDI: 00000000ffffffff RBP: ffff88810005d000 R08: 00000000ffffdfff R09: ffffffff831051c8 R10: ffffffff83055220 R11: 0000000000000000 R12: ffff8881c2458c00 R13: ffff88811923c540 R14: ffff88811923c5e8 R15: ffff8881c1bd9680 FS: 0000000000000000(0000) GS:ffff88a04acd0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f907c7a918c CR3: 0000000004024000 CR4: 0000000000350ef0 Call Trace: ? srso_return_thunk+0x5/0x5f btrfs_finish_ordered_io+0x4a/0x60 [btrfs] btrfs_work_helper+0xf9/0x490 [btrfs] process_one_work+0x204/0x590 ? srso_return_thunk+0x5/0x5f worker_thread+0x1d6/0x3d0 ? __pfx_worker_thread+0x10/0x10 kthread+0x118/0x230 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x205/0x260 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30

Consider process A calling writepages() with WB_SYNC_NONE. In zoned mode or for compressed writes, it locks several folios for delalloc and starts writing them out. Let's call the last locked folio folio X. Suppose the write range only partially covers folio X, leaving some pages dirty. Process A calls btrfs_subpage_set_writeback() when building a bio. This function call clears the TOWRITE tag of folio X, whose size = 8K and the block size = 4K. It is following state.

0 4K 8K |/////|/////| (flag: DIRTY, tag: DIRTY) <-----> Process A will write this range.

Now suppose process B concurrently calls writepages() with WB_SYNC_ALL. It calls tag_pages_for_writeback() to tag dirty folios with PAGECACHE_TAG_TOWRITE. Since folio X is still dirty, it gets tagged. Then, B collects tagged folios using filemap_get_folios_tag() and must wait for folio X to be written before returning from writepages().

0 4K 8K |/////|/////| (flag: DIRTY, tag: DIRTY|TOWRITE)

However, between tagging and collecting, process A may call btrfs_subpage_set_writeback() and clear folio X's TOWRITE tag. 0 4K 8K | |/////| (flag: DIRTY|WRITEBACK, tag: DIRTY)

As a result, process B won't see folio X in its batch, and returns without waiting for it. This breaks the WB_SYNC_ALL ordering requirement.

Fix this by using btrfs_subpage_set_writeback_keepwrite(), which retains the TOWRITE tag. We now manually clear the tag only after the folio becomes clean, via the xas operation.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

September 11, 2025

Last Modified

July 30, 2026

References (3)

Vendor Advisories for CVE-2025-39779(1)

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

Patch Availability(17)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-6.8 (6.8.0-100.100) @ noble2026-05-29ubuntu
ubuntulinux-tools-realtime-hwe-22.04 (6.8.1-1041.42~22.04.1) @ jammy2026-05-29ubuntu
ubuntulinux-tools-gcp-edge (6.8.0-1047.50~22.04.2) @ jammy2026-05-29ubuntu
ubuntulinux-tools-realtime-6.8.1 (6.8.1-1041.42) @ noble2026-05-29ubuntu
ubuntulinux-tools-fips-6.8 (6.8.0-100.100+fips1) @ noble2026-05-29ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1043.44) @ noble2026-05-29ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1047.50+fips1) @ noble2026-05-29ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-100.100~22.04.1) @ jammy2026-05-29ubuntu
ubuntulinux-tools-gke-64k-6.8 (6.8.0-1043.48) @ noble2026-05-29ubuntu
ubuntulinux-tools-lowlatency-hwe-20.04-edge (6.8.0-100.100.1) @ noble2026-05-29ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1046.49.1) @ noble2026-05-29ubuntu
ubuntulinux-tools-ibm-lts-24.04 (6.8.0-1044.44) @ noble2026-05-29ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1023.24) @ noble2026-05-29ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1046.52) @ noble2026-05-29ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1046.52+fips1) @ noble2026-05-29ubuntu
ubuntulinux-tools-azure-edge (6.8.0-1051.57~22.04.1) @ jammy2026-05-29ubuntu
linuxKernel @ 6.12.44—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

All Vendor Advisories

(16)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 40× 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. 2026-08-01 04:15 UTCEPSS rescore
  2. 2026-07-30 16:27 UTCEPSS rescore
  3. 2026-07-30 06:53 UTCEG score recompute
  4. 2026-07-30 06:53 UTCGHSA enrichment
  5. 2026-07-30 01:29 UTCEPSS rescore
  6. 2026-07-28 15:35 UTCEPSS rescore
  7. 2026-07-26 14:54 UTCEPSS rescore
  8. 2026-07-25 14:17 UTCEPSS rescore
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  10. 2026-07-24 14:17 UTCEPSS rescore
  11. 2026-07-23 20:11 UTCOSV refresh
  12. 2026-07-23 02:55 UTCEG score recompute
  13. 2026-07-22 14:07 UTCEPSS rescore
  14. 2026-07-22 14:07 UTCEPSS rescore
  15. 2026-07-21 15:24 UTCEPSS rescore
  16. 2026-07-20 17:07 UTCEPSS rescore
  17. 2026-07-19 14:30 UTCEPSS rescore
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  19. 2026-07-19 02:28 UTCEPSS rescore
  20. 2026-07-19 02:28 UTCEPSS rescore
  21. 2026-07-18 10:04 UTCEPSS rescore
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  23. 2026-07-16 17:02 UTCEPSS rescore
  24. 2026-07-15 16:57 UTCEPSS rescore
  25. 2026-07-15 16:57 UTCEPSS rescore
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  1. 2026-07-15 01:59 UTCEPSS rescore
  2. 2026-07-15 01:59 UTCEPSS rescore
  3. 2026-07-13 22:29 UTCEPSS rescore
  4. 2026-07-13 22:29 UTCEPSS rescore
  5. 2026-07-12 05:46 UTCEPSS rescore
  6. 2026-07-11 08:27 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 19:09 UTCEPSS rescore
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  10. 2026-07-07 13:45 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 14:41 UTCOSV refresh
  14. 2026-07-05 02:30 UTCEPSS rescore
  15. 2026-07-04 06:30 UTCEPSS rescore
  16. 2026-07-01 15:06 UTCEPSS rescore
  17. 2026-07-01 15:06 UTCEPSS rescore
  18. 2026-06-30 23:22 UTCEPSS rescore
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  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-28 14:07 UTCEPSS rescore
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 04:55 UTCEPSS rescore
  25. 2026-06-28 04:55 UTCEPSS rescore
  26. 2026-06-27 03:08 UTCEPSS rescore
  27. 2026-06-27 03:08 UTCEPSS rescore
  28. 2026-06-25 13:49 UTCEPSS rescore
  29. 2026-06-25 13:49 UTCEPSS rescore
  30. 2026-06-24 14:04 UTCEPSS rescore
  31. 2026-06-24 14:04 UTCEPSS rescore
  32. 2026-06-23 21:32 UTCEPSS rescore
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  34. 2026-06-22 14:25 UTCEPSS rescore
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  36. 2026-06-21 14:56 UTCEPSS rescore
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  38. 2026-06-21 01:59 UTCEPSS rescore
  39. 2026-06-21 01:59 UTCEPSS rescore
  40. 2026-06-19 19:25 UTCEPSS rescore
  41. 2026-06-19 19:25 UTCEPSS rescore
  42. 2026-06-18 17:52 UTCEPSS rescore
  43. 2026-06-18 17:52 UTCEPSS rescore
  44. 2026-06-18 03:05 UTCOSV refresh
  45. 2026-06-17 17:52 UTCEPSS rescore
  46. 2026-06-16 17:52 UTCEPSS rescore
  47. 2026-06-16 17:52 UTCEPSS rescore
  48. 2026-06-14 23:17 UTCEPSS rescore
  49. 2026-06-13 23:00 UTCEPSS rescore
  50. 2026-06-12 23:11 UTCEPSS rescore
  51. 2026-06-11 14:00 UTCEPSS rescore
  52. 2026-06-10 22:18 UTCEPSS rescore
  53. 2026-06-10 13:22 UTCEPSS rescore
  54. 2026-06-08 14:16 UTCEPSS rescore
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  56. 2026-06-07 15:24 UTCEPSS rescore
  57. 2026-06-05 22:46 UTCEPSS rescore
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  59. 2026-06-05 06:10 UTCEPSS rescore
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  61. 2026-06-04 13:12 UTCEPSS rescore
  62. 2026-06-04 13:12 UTCEPSS rescore
  63. 2026-06-02 20:12 UTCEPSS rescore
  64. 2026-06-01 13:51 UTCEPSS rescore
  65. 2026-06-01 13:51 UTCEPSS rescore
  66. 2026-05-31 22:30 UTCEPSS rescore
  67. 2026-05-31 22:30 UTCEPSS rescore
  68. 2026-05-31 00:16 UTCEPSS rescore
  69. 2026-05-29 23:00 UTCEG score recompute
  70. 2026-05-29 23:00 UTCVendor advisory
  71. 2026-05-29 23:00 UTCGHSA enrichment
  72. 2026-05-29 13:44 UTCEPSS rescore

Related CVEs(same product + same vendor)

Frequently asked(5)

What is CVE-2025-39779?
CVE-2025-39779 is a medium vulnerability published on September 11, 2025. In the Linux kernel, the following vulnerability has been resolved: btrfs: subpage: keep TOWRITE tag until folio is cleaned btrfssubpagesetwriteback() calls foliostart_writeback() the first time a folio is written back, and it also clears the PAGECACHETAGTOWRITE tag even if there are still dirty…
When was CVE-2025-39779 disclosed?
CVE-2025-39779 was first published in the National Vulnerability Database on September 11, 2025, with the most recent update on July 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-39779 actively exploited?
CVE-2025-39779 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.1% of all scored CVEs.
What is the CVSS score of CVE-2025-39779?
CVE-2025-39779 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-39779?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-39779, 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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