CVE-2026-89652: Linux kernel · ceph: bound copied dentry name length in NFS export get_name
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in eff8013c5a8916613c742ae5a2cc341cb605c0ae : patch Linux kernel as a priority.
Data as of 30 Oct 2026, 12:49 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 9.8 |
|---|
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in eff8013c5a8916613c742ae5a2cc341cb605c0ae, e7c2fd3893a7f7fcd7e8cf0b2c6348bb1e893df6, dff3d84d14142ea43ad61ef5d6b4de05ba16ba42 +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: ceph: bound copied dentry name length in NFS export get_name ceph_get_name() copies the MDS-supplied name into the caller's NAME_MAX-sized buffer with memcpy(name, rinfo->dname, rinfo->dname_len) and then writes name[rinfo->dname_len] = 0, without checking dname_len against NAME_MAX. A malicious or buggy MDS that returns a LOOKUPNAME reply with dname_len > NAME_MAX overflows the buffer. __get_snap_name() copies rde->name / rde->name_len the same unchecked way. Impact: a malicious or compromised Ceph MDS overflows the NAME_MAX name buffer in a client's NFS-export get_name path, a slab out-of-bounds write reported by KASAN. Reachable when a CephFS mount is re-exported over NFS. Add ceph_export_copy_name(), which rejects lengths above NAME_MAX with -ENAMETOOLONG before the copy, and use it in both ceph_get_name() and __get_snap_name().
References
- git.kernel.org/stable/c/aadfe588ad8032ea99bda259ae7b8d42854f8193 (opens in a new tab)
- git.kernel.org/stable/c/3cb09301c30909a7935e9de41f98eeb5ef7e4d40 (opens in a new tab)
- git.kernel.org/stable/c/dff3d84d14142ea43ad61ef5d6b4de05ba16ba42 (opens in a new tab)
- git.kernel.org/stable/c/a294064e0e0f81ea607b2f019e16888aa1b0a011 (opens in a new tab)
- git.kernel.org/stable/c/61d9f27b191b838b96b697ce0bfaee39a138243a (opens in a new tab)
- git.kernel.org/stable/c/06fb5e623cdc2402d6bb29be94d9beb9a826ffec (opens in a new tab)
- git.kernel.org/stable/c/e7c2fd3893a7f7fcd7e8cf0b2c6348bb1e893df6 (opens in a new tab)
- git.kernel.org/stable/c/eff8013c5a8916613c742ae5a2cc341cb605c0ae (opens in a new tab)