CyberSecBulletin
CVE-2026-52981NVD status: Modified

Linux: Missing Release of Memory after Effective Lifetime

Published Updated By the CyberSecBulletin desk

CVE-2026-52981 is a high-severity missing release of memory after effective lifetime vulnerability in Linux, with a CVSS 3.1 base score of 7.5 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 8a89054a1ec0767aec25ed2bbac933da6ba3cf5a, 9247d59ca15bf60a57dca08103f055d8a4340877, 0084712e0bee204b284510cdb63182fd5a30c2b7 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.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 8a89054a1ec0767aec25ed2bbac933da6ba3cf5a or 9247d59ca15bf60a57dca08103f055d8a4340877 or 0084712e0bee204b284510cdb63182fd5a30c2b7 or 63063ba60d2dc334e34f1e3f9271d7f3f6f30307, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.175 or 6.6.141 or 6.12.91 or 6.18.33, 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
LinuxLinux4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 up to, but not including, 8a89054a1ec0767aec25ed2bbac933da6ba3cf5a; 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 up to, but not including, 9247d59ca15bf60a57dca08103f055d8a4340877; 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 up to, but not including, 0084712e0bee204b284510cdb63182fd5a30c2b7; 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 up to, but not including, 63063ba60d2dc334e34f1e3f9271d7f3f6f30307; 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 up to, but not including, 445e45a2c3a078316a62d2d331a570cf34ef5079; 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 up to, but not including, 4438113be604ee67a7bf4f81da6e1cca41332ce4; 4.18a89054a1ec0767aec25ed2bbac933da6ba3cf5a, 9247d59ca15bf60a57dca08103f055d8a4340877, 0084712e0bee204b284510cdb63182fd5a30c2b7, 63063ba60d2dc334e34f1e3f9271d7f3f6f30307, 445e45a2c3a078316a62d2d331a570cf34ef5079, 4438113be604ee67a7bf4f81da6e1cca41332ce4
LinuxLinux Kernel4.1 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.141; 6.7 up to, but not including, 6.12.91; 6.13 up to, but not including, 6.18.33; 6.19 up to, but not including, 7.0.10; 7.16.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10

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
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: neigh: let neigh_xmit take skb ownership neigh_xmit always releases the skb, except when no neighbour table is found. But even the first added user of neigh_xmit (mpls) relied on neigh_xmit to release the skb (or queue it for tx). sashiko reported: If neigh_xmit() is called with an uninitialized neighbor table (for example, NEIGH_ND_TABLE when IPv6 is disabled), it returns -EAFNOSUPPORT and bypasses its internal out_kfree_skb error path. Because the return value of neigh_xmit() is ignored here, does this leak the SKB? Assume full ownership and remove the last code path that doesn't xmit or free skb.

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

The underlying weakness: Missing Release of Memory after Effective Lifetime

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

How developers prevent this class of flaw

  • Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC). To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.

More Missing Release of Memory after Effective Lifetime vulnerabilities (CWE-401)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Missing Release of Memory after Effective Lifetime vulnerabilities

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