CVE-2026-98079btrfs: zstd: fix lost wakeup when waiting for a workspace
- —Not scoredno CVSS score yet
- 0.20%Exploitation in 30 daysEPSS · top 90% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: zstd: fix lost wakeup when waiting for a workspace A writer can sleep forever in zstd_get_workspace() even though a workspace is free. When zstd_alloc_workspace() fails, the task is queued on zwsm->wait and schedules unconditionally, never re-testing the pool. zstd_put_workspace() publishes the workspace and then calls cond_wake_up(), which only wakes when a sleeper is already visible, so a workspace returned between the failed allocation and prepare_to_wait() wakes nobody. The window is wide: zstd_alloc_workspace() goes through kvmalloc() and may enter reclaim. Only a max level workspace triggers the wakeup and one is deliberately kept allocated as the fallback every waiter waits for, so once its wakeup is lost the writer stays in TASK_UNINTERRUPTIBLE until some other task happens to return one. Re-check the pool after prepare_to_wait() has published the waiter, and use the workspace if one turned up.
Timeline
ID reserved
By Linux
Published
- 26 days later
· 26 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Undergoing Analysis.
- EPSS (exploitation in 30 days)
- 0.20% · top 90% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 – < 14d982762945d9945c60bbd48b77df194dd8e28d
- affected 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 – < 844603cf842ee67640d33f350e3fa60f3de7fad3
- affected 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 – < d8f57049521948df5f50797141472fbbed3b0723
- affected 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 – < 0de9f31d447ae71ab08c7850a321682f8d2907c3
- affected 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 – < 2acb9f3d1cc8f65dc81ed55e238cbf8e5b60bff7
- affected 5.1
- unaffected < 5.1
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.53 – ≤ 6.18.*
- unaffected 7.2.7 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References5
- https://git.kernel.org/stable/c/14d982762945d9945c60bbd48b77df194dd8e28d (opens in a new tab)
- https://git.kernel.org/stable/c/844603cf842ee67640d33f350e3fa60f3de7fad3 (opens in a new tab)
- https://git.kernel.org/stable/c/d8f57049521948df5f50797141472fbbed3b0723 (opens in a new tab)
- https://git.kernel.org/stable/c/0de9f31d447ae71ab08c7850a321682f8d2907c3 (opens in a new tab)
- https://git.kernel.org/stable/c/2acb9f3d1cc8f65dc81ed55e238cbf8e5b60bff7 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-86909 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-98079)Record last updated .