CyberSecBulletin
CVE-2026-43493NVD status: Modified

Linux: Detection of Error Condition Without Action

Published Updated By the CyberSecBulletin desk

CVE-2026-43493 is a critical-severity detection of error condition without action 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 ae7e95638d956d556d74b9abb9e780d3bd3dcd9e, 1d7f07df450bac3301938fbc4251f2611be4084e, 76641449b28979ebd6c02e9598367e119e385236 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 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to ae7e95638d956d556d74b9abb9e780d3bd3dcd9e or 1d7f07df450bac3301938fbc4251f2611be4084e or 76641449b28979ebd6c02e9598367e119e385236 or 9f1cbca178c03188e201ed175251372149bb25f2, 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 6.6.140, 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
LinuxLinux5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, ae7e95638d956d556d74b9abb9e780d3bd3dcd9e; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, 1d7f07df450bac3301938fbc4251f2611be4084e; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, 76641449b28979ebd6c02e9598367e119e385236; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, 9f1cbca178c03188e201ed175251372149bb25f2; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, eb34e243df57e32f4c08fa191f3602ea19076276; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, 77d55bc8675ee851ed639dc9be77325a8024cf67; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, 46271895ddfb1ba41f89f7e0dffbe9c2bcf7380a; 5a1436beec5744029f3ac90b6fe71a698dcd6155 up to, but not including, 915b692e6cb723aac658c25eb82c58fd81235110; and 1 more rangesae7e95638d956d556d74b9abb9e780d3bd3dcd9e, 1d7f07df450bac3301938fbc4251f2611be4084e, 76641449b28979ebd6c02e9598367e119e385236, 9f1cbca178c03188e201ed175251372149bb25f2, eb34e243df57e32f4c08fa191f3602ea19076276, 77d55bc8675ee851ed639dc9be77325a8024cf67
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernel2.6.34 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, 6.6.140; 6.7 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.45.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27

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: crypto: pcrypt - Fix handling of MAY_BACKLOG requests MAY_BACKLOG requests can return EBUSY. Handle them by checking for that value and filtering out EINPROGRESS notifications.

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

The underlying weakness: Detection of Error Condition Without Action

The product detects a specific error, but takes no actions to handle the error.

How developers prevent this class of flaw

  • Properly handle each exception. This is the recommended solution. Ensure that all exceptions are handled in such a way that you can be sure of the state of your system at any given moment.
  • If a function returns an error, it is important to either fix the problem and try again, alert the user that an error has happened and let the program continue, or alert the user and close and cleanup the program.
  • Subject the product to extensive testing to discover some of the possible instances of where/how errors or return values are not handled. Consider testing techniques such as ad hoc, equivalence partitioning, robustness and fault tolerance, mutation, and fuzzing.

More Detection of Error Condition Without Action vulnerabilities (CWE-390)

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 Detection of Error Condition Without Action vulnerabilities

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