CyberSecBulletin
CVE-2026-64452NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64452 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited from the same local network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 9c2f5c0829a8c8b904dae36be6d8056b719ac605, 80b5c8779acee0550845394fb3e5176a398aa24c, cc27aea4d454abfb385ee2c9499c78b96db9b728 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 0.22% 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 9c2f5c0829a8c8b904dae36be6d8056b719ac605 or 80b5c8779acee0550845394fb3e5176a398aa24c or cc27aea4d454abfb385ee2c9499c78b96db9b728 or a8e3a94711134e898c6021a6b77374efa91b3639, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, 9c2f5c0829a8c8b904dae36be6d8056b719ac605; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, 80b5c8779acee0550845394fb3e5176a398aa24c; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, cc27aea4d454abfb385ee2c9499c78b96db9b728; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, a8e3a94711134e898c6021a6b77374efa91b3639; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, 593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, 0beccbcf50de125be5520d0ffc59af4bb8655482; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, b713aa0cc344f10f7a9928a230b5f5e780d04078; 92aa7c65d295f3cbb96904afe335f683e55584b8 up to, but not including, 1720db928e5a58ca7d75ac1d514c3b73fd7061a7; and 1 more ranges9c2f5c0829a8c8b904dae36be6d8056b719ac605, 80b5c8779acee0550845394fb3e5176a398aa24c, cc27aea4d454abfb385ee2c9499c78b96db9b728, a8e3a94711134e898c6021a6b77374efa91b3639, 593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168, 0beccbcf50de125be5520d0ffc59af4bb8655482
LinuxLinux Kernel4.1 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.45.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39

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
AdjacentThe attacker must be on the same local network segment.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
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:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: 6lowpan: fix NHC entry use-after-free on error path lowpan_nhc_do_uncompression() looks up an NHC descriptor while holding lowpan_nhc_lock. If the descriptor has no uncompress callback, the error path drops the lock before printing nhc->name. lowpan_nhc_del() removes descriptors under the same lock and then relies on synchronize_net() before the owning module can be unloaded. That only waits for net RX RCU readers. lowpan_header_decompress() is also exported and can be reached from callers that are not necessarily covered by the net core RX critical section, for example the Bluetooth 6LoWPAN L2CAP receive path. This leaves a race where one task drops lowpan_nhc_lock in the error path, another task unregisters and frees the matching descriptor after synchronize_net() returns, and the first task then dereferences nhc->name for the warning. With the post-unlock window widened, KASAN reports: BUG: KASAN: slab-use-after-free in lowpan_nhc_do_uncompression+0x1f4/0x220 Read of size 8 lowpan_nhc_do_uncompression lowpan_header_decompress Fix this by printing the warning before dropping lowpan_nhc_lock, so the descriptor name is read while unregister is still excluded. The malformed packet is still rejected with -ENOTSUPP.

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

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

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 Use After Free vulnerabilities

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