CyberSecBulletin
CVE-2026-64113NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64113 is a critical-severity use after free 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 3d931ac62411a7e43b85dba5fe45e1a4a91bd5cb, 6ef30384a50a50e4a484cddf341bc27de31aa3de, 55b3e91d62b2f7a24109b2d7c9f4c66d2e3b1ec1 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 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 3d931ac62411a7e43b85dba5fe45e1a4a91bd5cb or 6ef30384a50a50e4a484cddf341bc27de31aa3de or 55b3e91d62b2f7a24109b2d7c9f4c66d2e3b1ec1 or add70e2682c0ad3be2a5810bcf1bc13963ba4df9, 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 6.6.142, 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
LinuxLinuxbad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, 3d931ac62411a7e43b85dba5fe45e1a4a91bd5cb; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, 6ef30384a50a50e4a484cddf341bc27de31aa3de; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, 55b3e91d62b2f7a24109b2d7c9f4c66d2e3b1ec1; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, add70e2682c0ad3be2a5810bcf1bc13963ba4df9; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, a244395d8c563ed1bb26c3ef708db6aeeaa08084; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, dfef79e09ed2f5df975c98547f97f5d7f8982a24; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, e8768bcbe5cd30c4ea36a22022c9ffaa66903693; bad17234ba702a50aeec50ab04724ee58af89607 up to, but not including, 5d49b568c188dc77199d8d2b959c91da8cc27cf1; and 1 more ranges3d931ac62411a7e43b85dba5fe45e1a4a91bd5cb, 6ef30384a50a50e4a484cddf341bc27de31aa3de, 55b3e91d62b2f7a24109b2d7c9f4c66d2e3b1ec1, add70e2682c0ad3be2a5810bcf1bc13963ba4df9, a244395d8c563ed1bb26c3ef708db6aeeaa08084, dfef79e09ed2f5df975c98547f97f5d7f8982a24
LinuxLinux Kernel3.19 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, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.15.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34

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: ixgbevf: fix use-after-free in VEPA multicast source pruning ixgbevf_clean_rx_irq() prunes frames whose source MAC matches the VF's own address (VEPA multicast workaround) by freeing the skb and continuing to the next descriptor: dev_kfree_skb_irq(skb); continue; The skb pointer is declared outside the while loop and persists across iterations. Because the continue skips the "skb = NULL" reset at the bottom of the loop, the next iteration enters the "else if (skb)" path and calls ixgbevf_add_rx_frag() on the freed skb, dereferencing skb_shinfo(skb)->nr_frags - a use-after-free in NAPI softirq context. The sibling driver iavf already handles this correctly by nulling the pointer before continuing. Apply the same pattern here. I do not have ixgbevf hardware; the bug was found by static analysis (scan_drop_continue_loops.py + semgrep drop_continue_in_loop, multi-tool corroboration with the highest score in the scan). The UAF was confirmed under KASAN by loading a test module that reproduces the exact code pattern (alloc skb, kfree_skb, then read skb_shinfo(skb)->nr_frags): BUG: KASAN: slab-use-after-free in ixgbevf_uaf_test_init+0x100/0x1000 Read of size 8 at addr 000000006163ae78 by task insmod/30 freed 208-byte region [000000006163adc0, 000000006163ae90) QEMU emulates igb (82576) but not ixgbe (82599), and the igbvf VF driver does not include the VEPA source pruning path, so a full end-to-end reproduction with emulated hardware was not possible.

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: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

Spotted an error? Tell us.