Linux: Missing Release of Memory after Effective Lifetime
CVE-2026-43373 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 9891d7f4f1ede473c54b49776ae07755083eef06, fef5aa6e3bcf3c8053307642663a63b7362d7552, 81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a 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 0.5% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 9891d7f4f1ede473c54b49776ae07755083eef06 or fef5aa6e3bcf3c8053307642663a63b7362d7552 or 81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a or 59962588197863d0d746879f193905c0c6b3df49, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.167 or 6.6.130, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, 9891d7f4f1ede473c54b49776ae07755083eef06; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, fef5aa6e3bcf3c8053307642663a63b7362d7552; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, 81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, 59962588197863d0d746879f193905c0c6b3df49; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, 553366c271479c0d571dd1bb5d1bcde4747fb82e; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, b70c4e5e711931cdd56e6e905737b72f1e649189; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, 87138dde2d6937b12b967f28fe598a7d59000ae4; 138635cc27c9737f940c3aa80912ff7a61c825af up to, but not including, 5c3398a54266541610c8d0a7082e654e9ff3e259; and 1 more ranges | 9891d7f4f1ede473c54b49776ae07755083eef06, fef5aa6e3bcf3c8053307642663a63b7362d7552, 81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a, 59962588197863d0d746879f193905c0c6b3df49, 553366c271479c0d571dd1bb5d1bcde4747fb82e, b70c4e5e711931cdd56e6e905737b72f1e649189 |
| Linux | Linux Kernel | 4.8 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.19; 6.19 up to, but not including, 6.19.9; 7.0 | 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.19 |
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: net: ncsi: fix skb leak in error paths Early return paths in NCSI RX and AEN handlers fail to release the received skb, resulting in a memory leak. Specifically, ncsi_aen_handler() returns on invalid AEN packets without consuming the skb. Similarly, ncsi_rcv_rsp() exits early when failing to resolve the NCSI device, response handler, or request, leaving the skb unfreed.
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
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/553366c271479c0d571dd1bb5d1bcde4747fb82e
- git.kernel.org/stable/c/59962588197863d0d746879f193905c0c6b3df49
- git.kernel.org/stable/c/5c3398a54266541610c8d0a7082e654e9ff3e259
- git.kernel.org/stable/c/81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a
- git.kernel.org/stable/c/87138dde2d6937b12b967f28fe598a7d59000ae4
- git.kernel.org/stable/c/9891d7f4f1ede473c54b49776ae07755083eef06
- git.kernel.org/stable/c/b70c4e5e711931cdd56e6e905737b72f1e649189
- git.kernel.org/stable/c/fef5aa6e3bcf3c8053307642663a63b7362d7552
Recent Missing Release of Memory after Effective Lifetime vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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