CVE-2026-80561libceph: fix multiple unsafe decodes in decode_locker()

Description

In the Linux kernel, the following vulnerability has been resolved: libceph: fix multiple unsafe decodes in decode_locker() decode_locker() in cls_lock_client.c contains three unsafe decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads: 1. ceph_decode_copy() at the locker_id_t name field has no preceding bounds check. With p == end after ceph_start_decoding() accepts struct_len=0, this reads sizeof(ceph_entity_name) = 9 bytes past the validated buffer boundary. 2. *p += sizeof(struct ceph_timespec) after the locker_info_t header is an unchecked pointer advance. A malicious OSD can position p past end, causing all subsequent _safe checks to pass against a bogus boundary. 3. len = ceph_decode_32(p) has no preceding bounds check, and the immediately following *p += len is uncapped. A malicious OSD can send len=0xffffffff, advancing p gigabytes past end and escaping the decode window entirely. Fix all three by replacing bare operations with their safe variants: ceph_decode_copy -> ceph_decode_copy_safe *p += sizeof(...) -> ceph_decode_skip_n ceph_decode_32(p) -> ceph_decode_32_safe *p += len -> ceph_decode_skip_n A new label is added to return -EINVAL on any bounds violation. -EINVAL is appropriate here: the data received from the OSD is structurally malformed, which is an invalid argument to the decode contract regardless of whether the caller or the wire is at fault. Attacker model: a malicious or compromised OSD in a multi-tenant Ceph deployment can trigger this against any kernel client that issues the lock.get_info class method (e.g. during RBD exclusive lock acquisition) without any further privileges beyond OSD session establishment. [ idryomov: use ceph_decode_skip_string() to skip description, trim changelog ]

Timeline

Scores

EPSS (exploitation in 30 days)

0.51% · top 56% of all CVEs (14 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.

Affected products

• Linux · Linux

  • affected d4ed4a530562881cc5225050e42d96034f405aae – < 1ed45c8d96498725eb54f740172f9068d8673906
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < 6265103e78f0ee7e2518de9cf938b94bee9700a0
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < 3c3716dc06a34e4ca7f743f5fcfa07fbc5a11070
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < fa4aa86fff0c56799c2e3f51a88879053285f4a9
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < dbfd83f722a78446ec18a476ef7a38e52240b50a
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < d1bba38574d095f191557d397d9633f08cd966b1
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < 51c8d238fe7236de627ab1a1433694552a904136
  • affected d4ed4a530562881cc5225050e42d96034f405aae – < 437b6551cfcc235eea1d735a874f9d421f555e17

• Linux · Linux

  • affected 4.9
  • unaffected < 4.9
  • unaffected 5.10.266 – ≤ 5.10.*
  • unaffected 5.15.217 – ≤ 5.15.*
  • unaffected 6.1.184 – ≤ 6.1.*
  • unaffected 6.6.153 – ≤ 6.6.*
  • unaffected 6.12.105 – ≤ 6.12.*
  • unaffected 6.18.46 – ≤ 6.18.*
  • unaffected 7.1.10 – ≤ 7.1.*
  • unaffected 7.2 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-66476 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-80561](https://cveledger.app/badge/CVE-2026-80561.svg)](https://cveledger.app/cve/CVE-2026-80561)

Record last updated 16 Oct 2026, 19:26 UTC.