CyberSecBulletin
CVE-2026-68082NVD status: Received

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-68082 is a critical-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions c8ade01170a27d8ede0d761c255268af81e417f8, 001835c599899ef1bd3506a815110a6374451554, 7c422364acd93d7da1dfc27d6b54635a269653a1 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.5% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to c8ade01170a27d8ede0d761c255268af81e417f8 or 001835c599899ef1bd3506a815110a6374451554 or 7c422364acd93d7da1dfc27d6b54635a269653a1 or 02430f6f729b297e803d0605871f0a670b4eafd6, whichever matches your release line, or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxd4ed4a530562881cc5225050e42d96034f405aae up to, but not including, c8ade01170a27d8ede0d761c255268af81e417f8; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, 001835c599899ef1bd3506a815110a6374451554; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, 7c422364acd93d7da1dfc27d6b54635a269653a1; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, 02430f6f729b297e803d0605871f0a670b4eafd6; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, 57ba829804fe6d34bbac3b826c4b15c1caa54862; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, 89df5d71f83f8e2781286798fd8ae5e42cf5f1a7; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, a54be593d0b749161b08a1e56189b2cb9114267a; d4ed4a530562881cc5225050e42d96034f405aae up to, but not including, a109a556115271ca7896dcda7b4b7e45e156c227; and 1 more rangesc8ade01170a27d8ede0d761c255268af81e417f8, 001835c599899ef1bd3506a815110a6374451554, 7c422364acd93d7da1dfc27d6b54635a269653a1, 02430f6f729b297e803d0605871f0a670b4eafd6, 57ba829804fe6d34bbac3b826c4b15c1caa54862, 89df5d71f83f8e2781286798fd8ae5e42cf5f1a7

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: libceph: fix two unsafe bare decodes in decode_lockers() decode_lockers() in cls_lock_client.c contains two bare decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads: 1. ceph_decode_32(p) at the num_lockers field has no preceding bounds check. ceph_start_decoding() accepts struct_len=0 as valid -- the internal ceph_decode_need(p, end, 0, bad) always passes -- so when an OSD sends struct_len=0, ceph_start_decoding() returns success with p == end. The immediately following bare ceph_decode_32(p) then reads 4 bytes past the validated buffer boundary. The garbage value is passed directly to kzalloc_objs() as the locker count. The sibling function decode_watchers() in osd_client.c already uses ceph_decode_32_safe() after its own ceph_start_decoding() call. decode_lockers() was the only site using the bare variant. 2. ceph_decode_8(p) after the decode_locker() loop has no preceding bounds check. If an OSD crafts num_lockers such that the loop advances p exactly to end, the subsequent bare ceph_decode_8(p) reads one byte past the validated buffer boundary. The result is passed directly into *type, which is used as a lock type discriminator by callers, giving an OSD-controlled one-byte OOB read with direct influence over the lock type field. Fix both by replacing bare operations with their safe variants: ceph_decode_32(p) -> ceph_decode_32_safe(p, end, *num_lockers, err_inval) ceph_decode_8(p) -> ceph_decode_8_safe(p, end, *type, err_free_lockers) The goto targets differ intentionally: err_inval: is a new label returning -EINVAL directly. It is used for the pre-allocation failure path where *lockers is not yet allocated and must not be passed to ceph_free_lockers(). err_free_lockers: is the existing label. It is used for the post-allocation failure path where *lockers is allocated and must be freed. ret is set to -EINVAL before ceph_decode_8_safe() so that err_free_lockers returns the correct error code on bounds violation. Without this, err_free_lockers would return a stale ret value (0 from the successful decode_locker() loop), silently swallowing the error. -EINVAL is correct for both failure paths. The data received from the OSD is structurally malformed. -ENOMEM would misrepresent the failure class to callers and to stable@ backporters triaging error paths. 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). [ idryomov: trim changelog, formatting ]

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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