CyberSecBulletin
CVE-2026-52954NVD status: Modified

Linux: Reachable Assertion

Published Updated By the CyberSecBulletin desk

CVE-2026-52954 is a high-severity reachable assertion vulnerability in Linux, with a CVSS 3.1 base score of 7.5 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 c7bf7864e2924fa5508ac270b0e9364bc13d5a6c, f47430fc1f815e87406e2d3b4e476eff1bc7fd9b, 0b6a3bcb91bc5bfeda39f0df3b71bab62c13e9da 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 0.52% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to c7bf7864e2924fa5508ac270b0e9364bc13d5a6c or f47430fc1f815e87406e2d3b4e476eff1bc7fd9b or 0b6a3bcb91bc5bfeda39f0df3b71bab62c13e9da or 534ebc08df97c47d4c7596f336fa31ecbf91519c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.258 or 5.15.209 or 6.1.175 or 6.6.141, whichever matches your release line, or a later version.
  3. 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
LinuxLinux5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, c7bf7864e2924fa5508ac270b0e9364bc13d5a6c; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, f47430fc1f815e87406e2d3b4e476eff1bc7fd9b; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, 0b6a3bcb91bc5bfeda39f0df3b71bab62c13e9da; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, 534ebc08df97c47d4c7596f336fa31ecbf91519c; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, 80c73bd1b2b04355d1d0c29be8ccbd25a380905d; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, 4d2b37abda9536808655830d683dc491d31741a8; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, 0a1265a9ab875f92b6a3ffb497404f46cf9d76a3; 5cf9c4a9959b6273675310d14a834ef14fbca37c up to, but not including, d289478cfc0bcf81c7914200d6abdcb78bd04ded; and 1 more rangesc7bf7864e2924fa5508ac270b0e9364bc13d5a6c, f47430fc1f815e87406e2d3b4e476eff1bc7fd9b, 0b6a3bcb91bc5bfeda39f0df3b71bab62c13e9da, 534ebc08df97c47d4c7596f336fa31ecbf91519c, 80c73bd1b2b04355d1d0c29be8ccbd25a380905d, 4d2b37abda9536808655830d683dc491d31741a8
LinuxLinux Kernel4.13 up to, but not including, 5.10.258; 5.11 up to, but not including, 5.15.209; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.141; 6.7 up to, but not including, 6.12.91; 6.13 up to, but not including, 6.18.33; 6.19 up to, but not including, 7.0.10; 7.15.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33

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
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: libceph: handle rbtree insertion error in decode_choose_args() A message of type CEPH_MSG_OSD_MAP contains an OSD map that itself contains a CRUSH map. The received CRUSH map may optionally contain choose_args that get decoded in decode_choose_args(). In this function, num_choose_arg_maps is read from the message, and a corresponding number of crush_choose_arg_maps gets decoded afterwards. Each crush_choose_arg_map has a choose_args_index, which serves as the key when inserting it into the choose_args rbtree of the decoded crush_map. If a (potentially corrupted) message contains two crush_choose_arg_maps with the same index, the assertion in insert_choose_arg_map() triggers a kernel BUG when trying to insert the second crush_choose_arg_map. This patch fixes the issue by switching to the non-asserting rbtree insertion function and rejecting the message if the insertion fails. [ idryomov: changelog ]

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

The underlying weakness: Reachable Assertion

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

How developers prevent this class of flaw

  • If the assertion statement is required (e.g., for security or reliability), change the invoking code to avoid the conditions that trigger the assertion.
  • Consider changing the assertion to some other less fatal error. This might not be easy to implement, since other code may be needed to handle the error.
  • Make sensitive open/close operations non-reachable from directly user-controlled data (e.g. open/close resources)

More Reachable Assertion vulnerabilities (CWE-617)

Timeline

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

References

Recent Reachable Assertion vulnerabilities

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