Linux: Missing Release of Memory after Effective Lifetime
CVE-2026-53394 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 c9aefb2b5f11337c9202c5bd0c45d71198449718, 017a6150106b054cc84d1b0582d97bd3a74d4281, a10bf67fe06469a71a401f72f328237345d553c0 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 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to c9aefb2b5f11337c9202c5bd0c45d71198449718 or 017a6150106b054cc84d1b0582d97bd3a74d4281 or a10bf67fe06469a71a401f72f328237345d553c0 or 57aee7a35bb12753057c5b65d72d1f46c0e95b07, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.95 or 6.18.38 or 7.1.3, 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 | 23df17788c6212809848f836b10c4f85b16843a5 up to, but not including, c9aefb2b5f11337c9202c5bd0c45d71198449718; 23df17788c6212809848f836b10c4f85b16843a5 up to, but not including, 017a6150106b054cc84d1b0582d97bd3a74d4281; 23df17788c6212809848f836b10c4f85b16843a5 up to, but not including, a10bf67fe06469a71a401f72f328237345d553c0; 23df17788c6212809848f836b10c4f85b16843a5 up to, but not including, 57aee7a35bb12753057c5b65d72d1f46c0e95b07; 6.10 | c9aefb2b5f11337c9202c5bd0c45d71198449718, 017a6150106b054cc84d1b0582d97bd3a74d4281, a10bf67fe06469a71a401f72f328237345d553c0, 57aee7a35bb12753057c5b65d72d1f46c0e95b07 |
| Linux | Linux Kernel | 6.10 up to, but not including, 6.12.95; 6.13 up to, but not including, 6.18.38; 6.19 up to, but not including, 7.1.3 | 6.12.95, 6.18.38, 7.1.3 |
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: nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it calls release_openowner() and sets oo = NULL. Control then falls through past the `if (oo)` guard -- which would have freed any pre-allocated `new` -- and unconditionally executes `new = alloc_stateowner(...)`. If `new` was already allocated on a prior iteration, the pointer is silently overwritten and the previous allocation (slab object + owner name buffer) is leaked. This requires a race: two NFSv4.0 OPEN threads with the same owner string, where a concurrent thread inserts a new unconfirmed owner into the hash between retry iterations. The window is narrow but repeatable under adversarial conditions. Fix by adding `goto retry` after `oo = NULL` so the already-allocated `new` is reused on the next iteration rather than overwritten.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Missing Release of Memory after Effective Lifetime vulnerabilities
- 8.7 High severity
- 9.4 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
- 7.5 High severity
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