CyberSecBulletin
CVE-2026-63860NVD status: Analyzed

Linux: Improper Null Termination

Published Updated By the CyberSecBulletin desk

CVE-2026-63860 is a high-severity improper null termination vulnerability in Linux, with a CVSS 3.1 base score of 8.4 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists versions fcd07d3b8ee7a39b344d73aed69c1a68cd9eacdf, 87111356d58d86edb221ba144d261ed83a5b8bbe, abda65bdd13084c771842adaac1f652d0660dd82 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 fcd07d3b8ee7a39b344d73aed69c1a68cd9eacdf or 87111356d58d86edb221ba144d261ed83a5b8bbe or abda65bdd13084c771842adaac1f652d0660dd82 or 137b5918931d4d05aa8ea8d3adf67f7224eef63c, 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.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, fcd07d3b8ee7a39b344d73aed69c1a68cd9eacdf; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, 87111356d58d86edb221ba144d261ed83a5b8bbe; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, abda65bdd13084c771842adaac1f652d0660dd82; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, 137b5918931d4d05aa8ea8d3adf67f7224eef63c; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, 5877c043398d5fa0e93919a3d837e5cd7a98a961; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, f2c7b39dde2e61df8157066969cc2a408cd3dcd9; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, c26a0052cceed4c4d380ee5808b699f937fb58d8; 30dc5e63d6a5ad24894b5512d10b228d73645a44 up to, but not including, 6ed3d14fc45d3da6025e7fe4a6a09066856698e2; and 1 more rangesfcd07d3b8ee7a39b344d73aed69c1a68cd9eacdf, 87111356d58d86edb221ba144d261ed83a5b8bbe, abda65bdd13084c771842adaac1f652d0660dd82, 137b5918931d4d05aa8ea8d3adf67f7224eef63c, 5877c043398d5fa0e93919a3d837e5cd7a98a961, f2c7b39dde2e61df8157066969cc2a408cd3dcd9
LinuxLinux Kernel3.16 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, 7.0.105.10.258, 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
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
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:L/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: RDMA/core: Prefer NLA_NUL_STRING These attributes are evaluated as c-string (passed to strcmp), but NLA_STRING doesn't check for the presence of a \0 terminator. Either this needs to switch to nla_strcmp() and needs to adjust printf fmt specifier to not use plain %s, or this needs to use NLA_NUL_STRING. As the code has been this way for long time, it seems to me that userspace does include the terminating nul, even tough its not enforced so far, and thus NLA_NUL_STRING use is the simpler solution.

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

The underlying weakness: Improper Null Termination

The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.

How developers prevent this class of flaw

  • Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.
  • Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.
  • If performance constraints permit, special code can be added that validates null-termination of string buffers, this is a rather naive and error-prone solution.

More Improper Null Termination vulnerabilities (CWE-170)

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 Null Termination vulnerabilities

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