CyberSecBulletin
CVE-2026-64361NVD status: Analyzed

Linux: Integer Underflow (Wrap or Wraparound)

Published Updated By the CyberSecBulletin desk

CVE-2026-64361 is a high-severity integer underflow (wrap or wraparound) 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 c8dd112173c02adf539fe2ad34a45f5e0068780d, fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1, 671c3fcc2ad31c1311ea6414382a2d95104ae1b9 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 0.13% 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 c8dd112173c02adf539fe2ad34a45f5e0068780d or fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1 or 671c3fcc2ad31c1311ea6414382a2d95104ae1b9 or b6a481642ea1977be2f84dc08c5affd742c177e7, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.5 or 5.10.261 or 5.15.212 or 6.1.178, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux67ecc81f6492275c9c54280532f558483c99c90e up to, but not including, c8dd112173c02adf539fe2ad34a45f5e0068780d; a1a60e79502279f996e55052f50cc14919020475 up to, but not including, fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1; fe2891a9c43ab87d1a210d61e6438ca6936e2f62 up to, but not including, 671c3fcc2ad31c1311ea6414382a2d95104ae1b9; 384a66b89f9540a9a8cb0f48807697dfabaece4c up to, but not including, b6a481642ea1977be2f84dc08c5affd742c177e7; efc095b35b23297e419c2ab4fc1ed1a8f0781a29 up to, but not including, 7399c3baee7bb622a92f0b895cd4d3009a693f2b; a431930c9bac518bf99d6b1da526a7f37ddee8d8 up to, but not including, 607217f7ad419b53926f71e3f75001813bbc08ad; a431930c9bac518bf99d6b1da526a7f37ddee8d8 up to, but not including, c25d3c931a63e762fcaa9cb125b901c53b62403f; a431930c9bac518bf99d6b1da526a7f37ddee8d8 up to, but not including, 966cb76fb2857a4242cab6ea2ea17acf818a3da7; and 12 more rangesc8dd112173c02adf539fe2ad34a45f5e0068780d, fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1, 671c3fcc2ad31c1311ea6414382a2d95104ae1b9, b6a481642ea1977be2f84dc08c5affd742c177e7, 7399c3baee7bb622a92f0b895cd4d3009a693f2b, 607217f7ad419b53926f71e3f75001813bbc08ad
LinuxLinux Kernel5.4.297 up to, but not including, 5.5; 5.10.241 up to, but not including, 5.10.261; 5.15.190 up to, but not including, 5.15.212; 6.1.149 up to, but not including, 6.1.178; 6.6.103 up to, but not including, 6.6.145; 6.12.43 up to, but not including, 6.12.97; 6.15.11 up to, but not including, 6.16; 6.16.2 up to, but not including, 6.18.40; and 1 more ranges5.5, 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97

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: hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length check_and_correct_requested_length() compares (off + len) against node_size using u32 arithmetic. When the caller passes a large len value (e.g. from an underflowed subtraction in hfs_brec_remove()), off + len can wrap past 2^32 and produce a small result, causing the bounds check to pass when it should fail. For example, with off=14 and len=0xFFFFFFF2 (underflowed from data_off - keyoffset - size in hfs_brec_remove), off + len wraps to 6, which is less than a typical node_size of 512, so the check passes and the subsequent memmove reads ~4GB past the node buffer. Fix this by widening the addition to u64 before comparing against node_size. This prevents the u32 wrap while keeping the logic straightforward.

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

The underlying weakness: Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

More Integer Underflow (Wrap or Wraparound) vulnerabilities (CWE-191)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Integer Underflow (Wrap or Wraparound) vulnerabilities

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