CyberSecBulletin
CVE-2026-52912NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-52912 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 950d809f154dca04e5fbe5d3c8b9c5e44769cd57, a698ac8ab2561cf575d2d9f34095032651dd952e, 19924bdd8a45ebc72a7b84c57fd63057d1dc75ac 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 0.16% 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 950d809f154dca04e5fbe5d3c8b9c5e44769cd57 or a698ac8ab2561cf575d2d9f34095032651dd952e or 19924bdd8a45ebc72a7b84c57fd63057d1dc75ac or 1e5e20031c5eee8d2e490a90ff4d6a2feecfc3be, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.259 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
LinuxLinuxac28634456867b23b95faccba7997a62ec430603 up to, but not including, 950d809f154dca04e5fbe5d3c8b9c5e44769cd57; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, a698ac8ab2561cf575d2d9f34095032651dd952e; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, 19924bdd8a45ebc72a7b84c57fd63057d1dc75ac; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, 1e5e20031c5eee8d2e490a90ff4d6a2feecfc3be; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, 3823c27099cfe2482299065814adbaa771be9644; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, 15d464265120ab9818bd673af301deee09bedab2; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, 3fb0f5c0f64162a8c3f25616a4f1e340b921737f; ac28634456867b23b95faccba7997a62ec430603 up to, but not including, e196115ec330a18de415bdb9f5071aa9f08e53ce; and 1 more ranges950d809f154dca04e5fbe5d3c8b9c5e44769cd57, a698ac8ab2561cf575d2d9f34095032651dd952e, 19924bdd8a45ebc72a7b84c57fd63057d1dc75ac, 1e5e20031c5eee8d2e490a90ff4d6a2feecfc3be, 3823c27099cfe2482299065814adbaa771be9644, 15d464265120ab9818bd673af301deee09bedab2
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)V3.1.6 and later; V3.1.7 and laterNot stated
LinuxLinux Kernel4.7 up to, but not including, 5.10.259; 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; 7.15.10.259, 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
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: netfilter: nf_queue: hold bridge skb->dev while queued br_pass_frame_up() rewrites skb->dev from the ingress port to the bridge master before queueing bridge LOCAL_IN packets. NFQUEUE only holds references on state.in/out and bridge physdevs, so a queued bridge packet can retain a freed bridge master in skb->dev until reinjection. When the verdict is reinjected later, br_netif_receive_skb() re-enters the receive path with skb->dev still pointing at the freed bridge master, triggering a use-after-free. Store skb->dev in the queue entry, hold a reference on it for the queue lifetime, and use the saved device when dropping queued packets during NETDEV_DOWN handling.

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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