CVE-2026-89650: Linux kernel · ceph: bound num_export_targets array for mds info v2/v3
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% 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:H/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 that adds proper bounds checking for the num_export_targets array in ceph_mdsmap_decode() for all affected per-mds info versions (2 and 3). Users should apply the official Linux kernel patches that address this issue. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's Ceph filesystem client allows a malicious or compromised Ceph monitor to trigger an out-of-bounds read by sending a crafted MDS map with an oversized num_export_targets field in per-mds info version 2 or 3. This flaw occurs because the decode function does not properly check array bounds before advancing the decode cursor, leading to a kernel out-of-bounds read. The issue has been resolved by adding proper bounds checking for all relevant versions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89650 (opens in a new tab)
- git.kernel.org/stable/c/332c444f4dc6fa1e8b8637c9e82d29e97f768656 (opens in a new tab)
- git.kernel.org/stable/c/3bf7dba8dba9a05774b846affec61a3624ddba38 (opens in a new tab)
- git.kernel.org/stable/c/58c2d3e954c13694ef6e820a5e9456461bb9e7df (opens in a new tab)
- git.kernel.org/stable/c/a3eb169ee297aa99670ba927c659990bd1e453f3 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89650 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89650 (opens in a new tab)
- git.kernel.org/linus/a3eb169ee297aa99670ba927c659990bd1e453f3 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89650.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)