CyberSecBulletin
CVE-2026-63843NVD status: Analyzed

Linux: Improper Check for Unusual or Exceptional Conditions

Published Updated By the CyberSecBulletin desk

CVE-2026-63843 is a high-severity improper check for unusual or exceptional conditions vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 424510b60d4698a75a6ff71acdd88b528f0f39af, f26e3f7186cd6ecc93e6af102744d64c798dea7e, f9bc5633b761cff200c428f61ed0df6212b1c721 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 0.18% 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 424510b60d4698a75a6ff71acdd88b528f0f39af or f26e3f7186cd6ecc93e6af102744d64c798dea7e or f9bc5633b761cff200c428f61ed0df6212b1c721 or b65b7f3f3c18f797f81a2af7c97e2079900ad6db, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.12.91 or 6.18.33 or 7.0.10, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux8f98a715da8e906cff5c635f9eb5399b84751557 up to, but not including, 424510b60d4698a75a6ff71acdd88b528f0f39af; 8f98a715da8e906cff5c635f9eb5399b84751557 up to, but not including, f26e3f7186cd6ecc93e6af102744d64c798dea7e; 8f98a715da8e906cff5c635f9eb5399b84751557 up to, but not including, f9bc5633b761cff200c428f61ed0df6212b1c721; 8f98a715da8e906cff5c635f9eb5399b84751557 up to, but not including, b65b7f3f3c18f797f81a2af7c97e2079900ad6db; 6.7424510b60d4698a75a6ff71acdd88b528f0f39af, f26e3f7186cd6ecc93e6af102744d64c798dea7e, f9bc5633b761cff200c428f61ed0df6212b1c721, b65b7f3f3c18f797f81a2af7c97e2079900ad6db
LinuxLinux Kernel6.7 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; 7.16.12.91, 6.18.33, 7.0.10

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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
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:L/AC:L/PR:L/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: drm/amdgpu/jpeg: set no_user_fence for JPEG v4.0.5 ring JPEG rings do not support 64-bit user fence writes, reject CS submissions with user fences. (cherry picked from commit f05d0a4f21fc720116d6e238f23308b199891058)

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

The underlying weakness: Improper Check for Unusual or Exceptional Conditions

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Choose languages with features such as exception handling that force the programmer to anticipate unusual conditions that may generate exceptions. Custom exceptions may need to be developed to handle unusual business-logic conditions. Be careful not to pass sensitive exceptions back to the user (CWE-209, CWE-248).
  • Check the results of all functions that return a value and verify that the value is expected.
  • If using exception handling, catch and throw specific exceptions instead of overly-general exceptions (CWE-396, CWE-397). Catch and handle exceptions as locally as possible so that exceptions do not propagate too far up the call stack (CWE-705). Avoid unchecked or uncaught exceptions where feasible (CWE-248).

More Improper Check for Unusual or Exceptional Conditions vulnerabilities (CWE-754)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Check for Unusual or Exceptional Conditions vulnerabilities

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