CVE-2026-23018

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-01-31. 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: release path before initializing extent tree in btrfs_read_locked_inode()

In btrfs_read_locked_inode() we are calling btrfs_init_file_extent_tree() while holding a path with a read locked leaf from a subvolume tree, and btrfs_init_file_extent_tree() may do a GFP_KERNEL allocation, which can trigger reclaim.

This can create a circular lock dependency which lockdep warns about with the following splat:

[6.1433] ====================================================== [6.1574] WARNING: possible circular locking dependency detected [6.1583] 6.18.0+ #4 Tainted: G U [6.1591] ------------------------------------------------------ [6.1599] kswapd0/117 is trying to acquire lock: [6.1606] ffff8d9b6333c5b8 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1625] but task is already holding lock: [6.1633] ffffffffa4ab8ce0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x195/0xc60 [6.1646] which lock already depends on the new lock.

[6.1657] the existing dependency chain (in reverse order) is: [6.1667] -> #2 (fs_reclaim){+.+.}-{0:0}: [6.1677] fs_reclaim_acquire+0x9d/0xd0 [6.1685] __kmalloc_cache_noprof+0x59/0x750 [6.1694] btrfs_init_file_extent_tree+0x90/0x100 [6.1702] btrfs_read_locked_inode+0xc3/0x6b0 [6.1710] btrfs_iget+0xbb/0xf0 [6.1716] btrfs_lookup_dentry+0x3c5/0x8e0 [6.1724] btrfs_lookup+0x12/0x30 [6.1731] lookup_open.isra.0+0x1aa/0x6a0 [6.1739] path_openat+0x5f7/0xc60 [6.1746] do_filp_open+0xd6/0x180 [6.1753] do_sys_openat2+0x8b/0xe0 [6.1760] __x64_sys_openat+0x54/0xa0 [6.1768] do_syscall_64+0x97/0x3e0 [6.1776] entry_SYSCALL_64_after_hwframe+0x76/0x7e [6.1784] -> #1 (btrfs-tree-00){++++}-{3:3}: [6.1794] lock_release+0x127/0x2a0 [6.1801] up_read+0x1b/0x30 [6.1808] btrfs_search_slot+0x8e0/0xff0 [6.1817] btrfs_lookup_inode+0x52/0xd0 [6.1825] __btrfs_update_delayed_inode+0x73/0x520 [6.1833] btrfs_commit_inode_delayed_inode+0x11a/0x120 [6.1842] btrfs_log_inode+0x608/0x1aa0 [6.1849] btrfs_log_inode_parent+0x249/0xf80 [6.1857] btrfs_log_dentry_safe+0x3e/0x60 [6.1865] btrfs_sync_file+0x431/0x690 [6.1872] do_fsync+0x39/0x80 [6.1879] __x64_sys_fsync+0x13/0x20 [6.1887] do_syscall_64+0x97/0x3e0 [6.1894] entry_SYSCALL_64_after_hwframe+0x76/0x7e [6.1903] -> #0 (&delayed_node->mutex){+.+.}-{3:3}: [6.1913] __lock_acquire+0x15e9/0x2820 [6.1920] lock_acquire+0xc9/0x2d0 [6.1927] __mutex_lock+0xcc/0x10a0 [6.1934] __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1944] btrfs_evict_inode+0x20b/0x4b0 [6.1952] evict+0x15a/0x2f0 [6.1958] prune_icache_sb+0x91/0xd0 [6.1966] super_cache_scan+0x150/0x1d0 [6.1974] do_shrink_slab+0x155/0x6f0 [6.1981] shrink_slab+0x48e/0x890 [6.1988] shrink_one+0x11a/0x1f0 [6.1995] shrink_node+0xbfd/0x1320 [6.1002] balance_pgdat+0x67f/0xc60 [6.1321] kswapd+0x1dc/0x3e0 [6.1643] kthread+0xff/0x240 [6.1965] ret_from_fork+0x223/0x280 [6.1287] ret_from_fork_asm+0x1a/0x30 [6.1616] other info that might help us debug this:

[6.1561] Chain exists of: &delayed_node->mutex --> btrfs-tree-00 --> fs_reclaim

[6.1503] Possible unsafe locking scenario:

[6.1110] CPU0 CPU1 [6.1411] ---- ---- [6.1707] lock(fs_reclaim); [6.1998] lock(btrfs-tree-00); [6.1291] lock(fs_reclaim); [6.1581] lock(&del ---truncated---

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
1%
KEV
Not listed

Published

January 31, 2026

Last Modified

June 17, 2026

References (2)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.6—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.

Data Freshness Timeline

(refreshed 5× in last 7d / 31× 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. 2026-07-31 02:04 UTCOSV refresh
  3. 2026-07-27 14:13 UTCEPSS rescore
  4. 2026-07-25 14:17 UTCEPSS rescore
  5. 2026-07-25 14:17 UTCEPSS rescore
  6. 2026-07-24 14:17 UTCEPSS rescore
  7. 2026-07-23 14:18 UTCEPSS rescore
  8. 2026-07-23 14:18 UTCEPSS rescore
  9. 2026-07-23 03:06 UTCEG score recompute
  10. 2026-07-21 15:24 UTCEPSS rescore
  11. 2026-07-21 15:24 UTCEPSS rescore
  12. 2026-07-19 02:29 UTCEPSS rescore
  13. 2026-07-19 02:28 UTCEPSS rescore
  14. 2026-07-16 17:03 UTCEPSS rescore
  15. 2026-07-16 17:03 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 16:57 UTCEPSS rescore
  18. 2026-07-15 02:00 UTCEPSS rescore
  19. 2026-07-15 02:00 UTCEPSS rescore
  20. 2026-07-13 22:30 UTCEPSS rescore
  21. 2026-07-13 10:37 UTCOSV refresh
  22. 2026-07-12 05:46 UTCEPSS rescore
  23. 2026-07-12 05:46 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-08 15:15 UTCEPSS rescore
Show 61 more
  1. 2026-07-08 15:15 UTCEPSS rescore
  2. 2026-07-07 13:46 UTCEPSS rescore
  3. 2026-07-06 02:23 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-04 06:31 UTCEPSS rescore
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-01 15:06 UTCEPSS rescore
  8. 2026-07-01 15:06 UTCEPSS rescore
  9. 2026-06-29 14:06 UTCEPSS rescore
  10. 2026-06-28 14:07 UTCEPSS rescore
  11. 2026-06-28 14:07 UTCEPSS rescore
  12. 2026-06-28 04:56 UTCEPSS rescore
  13. 2026-06-28 04:56 UTCEPSS rescore
  14. 2026-06-27 03:08 UTCEPSS rescore
  15. 2026-06-25 13:49 UTCEPSS rescore
  16. 2026-06-25 13:49 UTCEPSS rescore
  17. 2026-06-25 03:01 UTCOSV refresh
  18. 2026-06-24 14:05 UTCEPSS rescore
  19. 2026-06-24 14:05 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
  21. 2026-06-23 21:32 UTCEPSS rescore
  22. 2026-06-21 01:59 UTCEPSS rescore
  23. 2026-06-21 01:59 UTCEPSS rescore
  24. 2026-06-18 17:52 UTCEPSS rescore
  25. 2026-06-17 17:53 UTCEPSS rescore
  26. 2026-06-15 17:48 UTCEPSS rescore
  27. 2026-06-14 23:18 UTCEPSS rescore
  28. 2026-06-13 23:00 UTCEPSS rescore
  29. 2026-06-13 23:00 UTCEPSS rescore
  30. 2026-06-12 23:12 UTCEPSS rescore
  31. 2026-06-11 14:00 UTCEPSS rescore
  32. 2026-06-10 22:18 UTCEPSS rescore
  33. 2026-06-10 13:22 UTCEPSS rescore
  34. 2026-06-08 14:17 UTCEPSS rescore
  35. 2026-06-08 14:17 UTCEPSS rescore
  36. 2026-06-07 23:12 UTCGHSA enrichment
  37. 2026-06-07 15:25 UTCEPSS rescore
  38. 2026-06-07 15:24 UTCEPSS rescore
  39. 2026-06-06 13:47 UTCEPSS rescore
  40. 2026-06-06 13:47 UTCEPSS rescore
  41. 2026-06-06 13:47 UTCEPSS rescore
  42. 2026-06-05 22:47 UTCEPSS rescore
  43. 2026-06-05 06:10 UTCEPSS rescore
  44. 2026-06-05 06:10 UTCEPSS rescore
  45. 2026-06-04 13:12 UTCEPSS rescore
  46. 2026-06-04 13:12 UTCEPSS rescore
  47. 2026-06-04 13:12 UTCEPSS rescore
  48. 2026-06-02 20:13 UTCEPSS rescore
  49. 2026-06-02 20:13 UTCEPSS rescore
  50. 2026-06-01 13:51 UTCEPSS rescore
  51. 2026-06-01 13:51 UTCEPSS rescore
  52. 2026-06-01 13:51 UTCEPSS rescore
  53. 2026-05-31 22:30 UTCEPSS rescore
  54. 2026-05-31 22:30 UTCEPSS rescore
  55. 2026-05-31 00:16 UTCEPSS rescore
  56. 2026-05-31 00:16 UTCEPSS rescore
  57. 2026-05-31 00:16 UTCEPSS rescore
  58. 2026-05-29 14:56 UTCEG score recompute
  59. 2026-05-29 14:56 UTCGHSA enrichment
  60. 2026-05-29 13:44 UTCEPSS rescore
  61. 2026-05-29 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-23018?
CVE-2026-23018 is a medium vulnerability published on January 31, 2026. In the Linux kernel, the following vulnerability has been resolved: btrfs: release path before initializing extent tree in btrfsreadlocked_inode() In btrfsreadlockedinode() we are calling btrfsinitfileextent_tree() while holding a path with a read locked leaf from a subvolume tree, and…
When was CVE-2026-23018 disclosed?
CVE-2026-23018 was first published in the National Vulnerability Database on January 31, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23018 actively exploited?
CVE-2026-23018 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 99.0% of all scored CVEs.
What is the CVSS score of CVE-2026-23018?
CVE-2026-23018 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23018?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23018, 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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