CVE-2026-43299

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-05-08. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
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

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:

btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()

[BUG] There is a bug report that when btrfs hits ENOSPC error in a critical path, btrfs flips RO (this part is expected, although the ENOSPC bug still needs to be addressed).

The problem is after the RO flip, if there is a read repair pending, we can hit the ASSERT() inside btrfs_repair_io_failure() like the following:

BTRFS info (device vdc): relocating block group 30408704 flags metadata|raid1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -28) WARNING: fs/btrfs/extent-tree.c:3235 at __btrfs_free_extent.isra.0+0x453/0xfd0, CPU#1: btrfs/383844 Modules linked in: kvm_intel kvm irqbypass [...] ---[ end trace 0000000000000000 ]--- BTRFS info (device vdc state EA): 2 enospc errors during balance BTRFS info (device vdc state EA): balance: ended with status: -30 BTRFS error (device vdc state EA): parent transid verify failed on logical 30556160 mirror 2 wanted 8 found 6 BTRFS error (device vdc state EA): bdev /dev/nvme0n1 errs: wr 0, rd 0, flush 0, corrupt 10, gen 0 [...] assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 ------------[ cut here ]------------ assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 kernel BUG at fs/btrfs/bio.c:938! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 868 Comm: kworker/u8:13 Tainted: G W N 6.19.0-rc6+ #4788 PREEMPT(full) Tainted: [W]=WARN, [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Workqueue: btrfs-endio simple_end_io_work RIP: 0010:btrfs_repair_io_failure.cold+0xb2/0x120 RSP: 0000:ffffc90001d2bcf0 EFLAGS: 00010246 RAX: 0000000000000051 RBX: 0000000000001000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8305cf42 RDI: 00000000ffffffff RBP: 0000000000000002 R08: 00000000fffeffff R09: ffffffff837fa988 R10: ffffffff8327a9e0 R11: 6f69747265737361 R12: ffff88813018d310 R13: ffff888168b8a000 R14: ffffc90001d2bd90 R15: ffff88810a169000 FS: 0000000000000000(0000) GS:ffff8885e752c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 ------------[ cut here ]------------

[CAUSE] The cause of -ENOSPC error during the test case btrfs/124 is still unknown, although it's known that we still have cases where metadata can be over-committed but can not be fulfilled correctly, thus if we hit such ENOSPC error inside a critical path, we have no choice but abort the current transaction.

This will mark the fs read-only.

The problem is inside the btrfs_repair_io_failure() path that we require the fs not to be mount read-only. This is normally fine, but if we are doing a read-repair meanwhile the fs flips RO due to a critical error, we can enter btrfs_repair_io_failure() with super block set to read-only, thus triggering the above crash.

[FIX] Just replace the ASSERT() with a proper return if the fs is already read-only.

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
2%
KEV
Not listed

Published

May 8, 2026

Last Modified

May 15, 2026

Advisory Details (2)

Auto-updated Jun 17, 2026
No patch confirmed yet.
generic

btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f6df18c001e3dcebc08482d0adeacd0cfea08593
generic

btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3

Vendor Advisories for CVE-2026-43299(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.19.6—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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 7.2~rc5-1~exp1 (496 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 7.2~rc5-1~exp1 (335 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.2~rc5-1~exp1 (160 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (113 versions)6.19.6-1—

Data Freshness Timeline

(refreshed 3× in last 7d / 41× 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.

Showing the most recent 100 of 154 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
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  1. 2026-08-12 16:49 UTCGHSA enrichment
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  4. 2026-08-11 05:50 UTCGHSA enrichment
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  7. 2026-08-10 04:49 UTCGHSA enrichment
  8. 2026-08-09 13:46 UTCEPSS rescore
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  10. 2026-08-09 03:48 UTCGHSA enrichment
  11. 2026-08-08 16:37 UTCEPSS rescore
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  18. 2026-08-05 22:10 UTCGHSA enrichment
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  22. 2026-08-04 05:29 UTCEG score recompute
  23. 2026-08-04 05:29 UTCGHSA enrichment
  24. 2026-08-03 10:36 UTCEPSS rescore
  25. 2026-08-03 04:26 UTCGHSA enrichment
  26. 2026-08-02 03:11 UTCEG score recompute
  27. 2026-08-02 03:11 UTCGHSA enrichment
  28. 2026-08-02 02:27 UTCEPSS rescore
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  44. 2026-07-16 05:49 UTCOSV refresh
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Frequently asked(5)

What is CVE-2026-43299?
CVE-2026-43299 is a medium vulnerability published on May 8, 2026. In the Linux kernel, the following vulnerability has been resolved: btrfs: do not ASSERT() when the fs flips RO inside btrfsrepairio_failure() [BUG] There is a bug report that when btrfs hits ENOSPC error in a critical path, btrfs flips RO (this part is expected, although the ENOSPC bug still needs…
When was CVE-2026-43299 disclosed?
CVE-2026-43299 was first published in the National Vulnerability Database on May 8, 2026, with the most recent update on May 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43299 actively exploited?
CVE-2026-43299 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 98.1% of all scored CVEs.
What is the CVSS score of CVE-2026-43299?
CVE-2026-43299 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-43299?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43299, 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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