CyberSecBulletin
CVE-2026-64115NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64115 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 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 1e19f08552b90070ed18bafb1763c78297823af6, 1dd531e28f61edd286edc486ab068f135b5ae1eb, ecda37f8faab3220da199335e42564cb7a9ad145 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 0.14% 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 1e19f08552b90070ed18bafb1763c78297823af6 or 1dd531e28f61edd286edc486ab068f135b5ae1eb or ecda37f8faab3220da199335e42564cb7a9ad145 or cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb, 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.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxd021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, 1e19f08552b90070ed18bafb1763c78297823af6; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, 1dd531e28f61edd286edc486ab068f135b5ae1eb; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, ecda37f8faab3220da199335e42564cb7a9ad145; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, 47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, 440447699c681e26ed58e9c309cad718270a18b4; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, 9fe74e42914c851d68069713b7b917a9c33faf26; d021c344051af91f42c5ba9fdedc176740cbd238 up to, but not including, 99e22ddf4edb63dc8382bc028af928056d3450cf; and 1 more ranges1e19f08552b90070ed18bafb1763c78297823af6, 1dd531e28f61edd286edc486ab068f135b5ae1eb, ecda37f8faab3220da199335e42564cb7a9ad145, cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb, 47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9, 440447699c681e26ed58e9c309cad718270a18b4
LinuxLinux Kernel3.9 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
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
ChangedThe attack can reach beyond the vulnerable component into other systems.
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:C/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: vsock/vmci: fix UAF when peer resets connection during handshake vmci_transport_recv_connecting_server() returned err = 0 for a peer RST in its default switch arm: err = pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL; That made vmci_transport_recv_listen() skip vsock_remove_pending(), leaving the pending socket on the listener's pending_links with sk_state = TCP_CLOSE while destroy: still dropped the explicit reference taken before schedule_delayed_work(). One second later vsock_pending_work() observed is_pending=true and performed full cleanup: vsock_remove_pending() then the two trailing sock_put(sk) calls -- the first reached refcount 0 and __sk_freed the socket, and the second wrote into the freed object: BUG: KASAN: slab-use-after-free in refcount_warn_saturate Write of size 4 at addr ffff88800b1cac80 by task kworker Workqueue: events vsock_pending_work Treat peer RST like any other unexpected packet type (err = -EINVAL). All destroy: arms now return err < 0, so vmci_transport_recv_listen() removes pending from pending_links synchronously and vsock_pending_work() takes the is_pending=false / !rejected branch, dropping only its own work reference. This also closes the multi-packet race Sashiko reported on v2: pending is removed from the list before any subsequent packet can find it. The pre-existing sk_acceptq_removed() gap on the err < 0 path of vmci_transport_recv_listen() that Sashiko also noted is not introduced or changed by this patch. Tested on lts-6.12.79 with KASAN: 52/100 unpatched -> 0/100 patched.

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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