CVE-2026-89647: Linux kernel · ceph: do not repeat ceph_trim_dentries() if no progress possible
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and has been applied to the affected Linux kernel versions. Users should update to patched kernel versions to resolve this issue. No additional mitigation is required once the patch is applied.
Description
A vulnerability in the Linux kernel's Ceph filesystem component caused a busy loop in the ceph_trim_dentries() function when no progress was possible during lease reclamation. This loop led to excessive CPU consumption without making progress, especially when there was no cap pressure and all leases were valid. The issue was fixed by modifying lease handling logic to avoid unnecessary retries and list churn, significantly reducing CPU usage.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89647 (opens in a new tab)
- git.kernel.org/stable/c/37d6edb2f03b29399a3a337fae78674de51e1695 (opens in a new tab)
- git.kernel.org/stable/c/3d122b2feb1dd76bb5041bdea5e1e1b007d8d415 (opens in a new tab)
- git.kernel.org/stable/c/5a541eb401acb89d791da41189d7a79220164b93 (opens in a new tab)
- git.kernel.org/stable/c/e7d7aa7b730178278109c41fa1b17b06873065d5 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89647 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89647 (opens in a new tab)
- git.kernel.org/linus/e7d7aa7b730178278109c41fa1b17b06873065d5 (opens in a new tab)