CVE-2026-23036

UNRATEDCVSS · not yet scored

Also known asEUVD-2026-5058 (ENISA EUVD) · GHSA-v7cw-956x-792r (GitHub Security Advisories)Source: ENISA EUVD

—
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS v2: —Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

btrfs: release path before iget_failed() in btrfs_read_locked_inode()

In btrfs_read_locked_inode() if we fail to lookup the inode, we jump to the 'out' label with a path that has a read locked leaf and then we call iget_failed(). This can result in a ABBA deadlock, since iget_failed() triggers inode eviction and that causes the release of the delayed inode, which must lock the delayed inode's mutex, and a task updating a delayed inode starts by taking the node's mutex and then modifying the inode's subvolume btree.

Syzbot reported the following lockdep splat for this:

====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ btrfs-cleaner/8725 is trying to acquire lock: ffff0000d6826a48 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290

but task is already holding lock: ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (btrfs-tree-00){++++}-{4:4}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x198/0x39c kernel/locking/lockdep.c:5889 up_read+0x24/0x3c kernel/locking/rwsem.c:1632 btrfs_tree_read_unlock+0xdc/0x298 fs/btrfs/locking.c:169 btrfs_tree_unlock_rw fs/btrfs/locking.h:218 [inline] btrfs_search_slot+0xa6c/0x223c fs/btrfs/ctree.c:2133 btrfs_lookup_inode+0xd8/0x38c fs/btrfs/inode-item.c:395 __btrfs_update_delayed_inode+0x124/0xed0 fs/btrfs/delayed-inode.c:1032 btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1118 [inline] __btrfs_commit_inode_delayed_items+0x15f8/0x1748 fs/btrfs/delayed-inode.c:1141 __btrfs_run_delayed_items+0x1ac/0x514 fs/btrfs/delayed-inode.c:1176 btrfs_run_delayed_items_nr+0x28/0x38 fs/btrfs/delayed-inode.c:1219 flush_space+0x26c/0xb68 fs/btrfs/space-info.c:828 do_async_reclaim_metadata_space+0x110/0x364 fs/btrfs/space-info.c:1158 btrfs_async_reclaim_metadata_space+0x90/0xd8 fs/btrfs/space-info.c:1226 process_one_work+0x7e8/0x155c kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3427 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

-> #0 (&delayed_node->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 btrfs_release_delayed_node fs/btrfs/delayed-inode.c:315 [inline] btrfs_remove_delayed_node+0x68/0x84 fs/btrfs/delayed-inode.c:1326 btrfs_evict_inode+0x578/0xe28 fs/btrfs/inode.c:5587 evict+0x414/0x928 fs/inode.c:810 iput_final fs/inode.c:1914 [inline] iput+0x95c/0xad4 fs/inode.c:1966 iget_failed+0xec/0x134 fs/bad_inode.c:248 btrfs_read_locked_inode+0xe1c/0x1234 fs/btrfs/inode.c:4101 btrfs_iget+0x1b0/0x264 fs/btrfs/inode.c:5837 btrfs_run_defrag_inode fs/btrfs/defrag.c:237 [inline] btrfs_run_defrag_inodes+0x520/0xdc4 fs/btrf ---truncated---

CVSS v3
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EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
—
EPSS PROB
0.2%
EPSS %ILE
12th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

EG Severity
Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS. FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the BOD 26-04 block below.

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

January 31, 2026

Last Modified

June 17, 2026

References (2)

Patch Availability(7)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-realtime-hwe-24.04 (6.17.0-1018.20~24.04.1) @ noble2026-10-27ubuntu
ubuntulinux-tools-nvidia-hwe-24.04 (6.17.0-1031.31) @ noble2026-10-27ubuntu
ubuntulinux-tools-azure-6.17 (6.17.0-1021.21~24.04.1) @ noble2026-10-27ubuntu
ubuntulinux-tools-azure-fde-6.17 (6.17.0-1018.18~24.04.1) @ noble2026-10-27ubuntu
ubuntulinux-tools-oem-6.17 (6.17.0-1030.30) @ noble2026-10-27ubuntu
ubuntulinux-tools-oracle-64k-6.17 (6.17.0-1019.19~24.04.3+1) @ noble2026-10-27ubuntu
linuxKernel @ 6.18.7 (fixes >=6.13.0)—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

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.18~rc7-1~exp1 (97 versions)
  • every version up to 6.18.8-1: fixed in 6.18.8-1
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All Vendor Advisories

(6)

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 time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 235 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 136 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  2. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  3. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  4. 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  5. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  6. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  7. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  8. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  9. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  10. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  11. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  12. 2026-10-27 10:48 UTCEG score recompute
  13. 2026-10-27 10:48 UTCVendor advisory
  14. 2026-10-27 10:48 UTCGHSA enrichmentGHSA-v7cw-956x-792r
  15. 2026-10-27 03:55 UTCOSV refresh
  16. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  17. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  18. 2026-10-25 14:41 UTCEG score recompute
  19. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  20. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  21. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  22. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  23. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  25. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
Show 74 more
  1. 2026-10-18 03:55 UTCEG score recompute
  2. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  4. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  5. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  6. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  7. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  8. 2026-10-12 16:21 UTCEG score recompute
  9. 2026-10-11 20:03 UTCEG score recompute
  10. 2026-10-11 17:16 UTCEG score recompute
  11. 2026-10-11 14:48 UTCEG score recompute
  12. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  13. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  14. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  15. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  16. 2026-10-07 10:24 UTCOSV refresh
  17. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  18. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  19. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  20. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  21. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  22. 2026-09-29 15:21 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  23. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  25. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  26. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  27. 2026-09-24 14:03 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  28. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  29. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  30. 2026-09-17 16:06 UTCOSV refresh
  31. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  32. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  33. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  34. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  35. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  36. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  37. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  38. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  39. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  40. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  41. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  42. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  43. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  44. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  45. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  46. 2026-08-29 16:43 UTCOSV refresh
  47. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  48. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  49. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  50. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  51. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  52. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  53. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  54. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  55. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  56. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  57. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  58. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  59. 2026-08-13 03:55 UTCVendor advisory
  60. 2026-08-13 03:55 UTCGHSA enrichmentGHSA-v7cw-956x-792r
  61. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  62. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  63. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  64. 2026-08-09 16:16 UTCVendor advisory
  65. 2026-08-09 16:16 UTCGHSA enrichmentGHSA-v7cw-956x-792r
  66. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  67. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  68. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  69. 2026-08-06 04:37 UTCVendor advisory
  70. 2026-08-06 04:37 UTCGHSA enrichmentGHSA-v7cw-956x-792r
  71. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  72. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  73. 2026-08-04 10:38 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  74. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.2% · 9th percentile

Related CVEs(same vendor)

Frequently asked(4)

What is CVE-2026-23036?
CVE-2026-23036 is a vulnerability whose severity is not yet rated; its CVE record was published on January 31, 2026. In the Linux kernel, the following vulnerability has been resolved: btrfs: release path before iget_failed() in btrfs_read_locked_inode() In btrfs_read_locked_inode() if we fail to lookup the inode, we jump to the 'out' label with a path that has a read locked leaf and then we call iget_failed().…
When was the CVE record for CVE-2026-23036 published?
The CVE record for CVE-2026-23036 was published on January 31, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-23036 actively exploited?
CVE-2026-23036 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (12th percentile of EPSS-scored CVEs).
How do I remediate CVE-2026-23036?
A fix for CVE-2026-23036 is available: update to the fixed version the vendor names in its advisory.

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