CyberSecBulletin
CVE-2026-46120NVD status: Undergoing Analysis

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-46120 is a high-severity use after free 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 7bd0f2b162b426b343a114e1b329f0d8d14fdc6e, 01b71ff2857d3598337de11e7840a8e3ff21553c, 0fcf6731706f73494245a9c0d64f93bebf95bb51 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 7bd0f2b162b426b343a114e1b329f0d8d14fdc6e or 01b71ff2857d3598337de11e7840a8e3ff21553c or 0fcf6731706f73494245a9c0d64f93bebf95bb51 or eca62bb0569de4d43a4dac06a2092a9d4ca1d702, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.17 or 5.10.258 or 5.15.209 or 6.1.175, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux2d665034f239412927b1e71329f20f001c92da09 up to, but not including, 7bd0f2b162b426b343a114e1b329f0d8d14fdc6e; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, 01b71ff2857d3598337de11e7840a8e3ff21553c; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, 0fcf6731706f73494245a9c0d64f93bebf95bb51; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, eca62bb0569de4d43a4dac06a2092a9d4ca1d702; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, 311fdd26eb4443d43b909cc67a10f3a5fd1b21b2; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, cf7fc624329e76c6394653d12353e1d033adea91; 2d665034f239412927b1e71329f20f001c92da09 up to, but not including, 1d324c2f43f70c965f25c58cc3611c779adbe47e; and 3 more ranges7bd0f2b162b426b343a114e1b329f0d8d14fdc6e, 01b71ff2857d3598337de11e7840a8e3ff21553c, 0fcf6731706f73494245a9c0d64f93bebf95bb51, eca62bb0569de4d43a4dac06a2092a9d4ca1d702, 311fdd26eb4443d43b909cc67a10f3a5fd1b21b2, e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernel4.16.12 up to, but not including, 4.17; 4.17.1 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, 6.6.140; 6.7 up to, but not including, 6.12.88; 6.13 up to, but not including, 6.18.30; 6.19 up to, but not including, 7.0.7; and 2 more ranges4.17, 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88

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: ip6_gre: Use cached t->net in ip6erspan_changelink(). After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns ip6gre hash via link_net. ip6erspan_changelink() was not converted in that series and still uses dev_net(dev), which diverges from the device's creation netns after IFLA_NET_NS_FD migration. This re-inserts the tunnel into the wrong per-netns hash. The original netns keeps a stale entry. When that netns is later destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a slab-use-after-free reported by KASAN, followed by a kernel BUG at net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify(). Reachable from an unprivileged user namespace (unshare --user --map-root-user --net). ip6gre_changelink() earlier in the same file already uses the cached t->net; only ip6erspan_changelink() has the wrong shape.

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

Spotted an error? Tell us.