CVE-2026-89648: Linux kernel · ceph: cap delegated inode count in ceph_parse_deleg_inos()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 14:05 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 versions to prevent exploitation. Since the vulnerability is resolved by bounding delegated inode counts and interval lengths, no additional mitigation steps are required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's Ceph client was resolved that allowed a malicious or compromised Ceph Metadata Server (MDS) to cause unbounded CPU usage or memory growth by sending large or malformed delegated inode intervals. The flaw involved unbounded loops and data structure growth when processing delegated inode intervals, which could be exploited to degrade client performance. The fix introduces strict caps on the number of delegated inodes per session and the aggregate interval length per reply, preventing resource exhaustion. This vulnerability affects specific Linux kernel versions used in the linux-hwe-edge product line.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89648 (opens in a new tab)
- git.kernel.org/stable/c/4bd3158bd62466d57ed72a3f7bc5f205fedd6919 (opens in a new tab)
- git.kernel.org/stable/c/c040e139f1a629b767f900bbbc3f9892c290ed85 (opens in a new tab)
- git.kernel.org/stable/c/f341270ac5f5077804d7837ce77b0f0df1cea29d (opens in a new tab)
- ubuntu.com/security/CVE-2026-89648 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89648 (opens in a new tab)
- git.kernel.org/linus/4bd3158bd62466d57ed72a3f7bc5f205fedd6919 (opens in a new tab)