CyberSecBulletin
CVE-2026-53397NVD status: Modified

Linux: Missing Release of Memory after Effective Lifetime

Published Updated By the CyberSecBulletin desk

CVE-2026-53397 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 b2eb1ffd511d1b3c3e21122f97cbbccea411e277, b94c4be77682aab06d65ca7296149e3bcfb37353, 887f92ceccf3eacd5f2402db21254d66372fae00 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 b2eb1ffd511d1b3c3e21122f97cbbccea411e277 or b94c4be77682aab06d65ca7296149e3bcfb37353 or 887f92ceccf3eacd5f2402db21254d66372fae00 or 1e96239fddcefacf6afe6c498357be68eacbcabc, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.260 or 5.15.211 or 6.1.177 or 6.6.144, 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
LinuxLinuxa257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, b2eb1ffd511d1b3c3e21122f97cbbccea411e277; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, b94c4be77682aab06d65ca7296149e3bcfb37353; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, 887f92ceccf3eacd5f2402db21254d66372fae00; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, 1e96239fddcefacf6afe6c498357be68eacbcabc; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, bd69a825485168ef74e815ecb286754b570fdcc7; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, 136b416593f1349cf6f72c8e3d18f0f204ee8545; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, a5b42c1e4ff2befaa6b96f7cbf32174751eba083; a257cdd0e2179630d3201c32ba14d7fcb3c3a055 up to, but not including, 0853ac544c590880d797b04daa33fcb72b6be0e1; and 1 more rangesb2eb1ffd511d1b3c3e21122f97cbbccea411e277, b94c4be77682aab06d65ca7296149e3bcfb37353, 887f92ceccf3eacd5f2402db21254d66372fae00, 1e96239fddcefacf6afe6c498357be68eacbcabc, bd69a825485168ef74e815ecb286754b570fdcc7, 136b416593f1349cf6f72c8e3d18f0f204ee8545
LinuxLinux Kernel2.6.13 up to, but not including, 5.10.260; 5.11 up to, but not including, 5.15.211; 5.16 up to, but not including, 6.1.177; 6.2 up to, but not including, 6.6.144; 6.7 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, 7.1.35.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38

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: fix posix_acl leak on SETACL decode failure nfsaclsvc_decode_setaclargs() and nfs3svc_decode_setaclargs() each call nfs_stream_decode_acl() twice, first for NFS_ACL and then for NFS_DFACL. Each successful call transfers ownership of a freshly allocated posix_acl into argp->acl_access or argp->acl_default. If the first call succeeds but the second fails, the decoder returns false and argp->acl_access is left dangling. ACLPROC2_SETACL.pc_release was wired to nfssvc_release_attrstat and ACLPROC3_SETACL.pc_release was wired to nfs3svc_release_fhandle. Both only call fh_put() and have no knowledge of the ACL fields on argp. The posix_acl_release() pairs sat at the out: labels inside nfsacld_proc_setacl() and nfsd3_proc_setacl(), but svc_process() skips pc_func when pc_decode returns false, so that cleanup is unreachable on decode failure: svc_process_common() pc_decode() /* decode_setaclargs: false */ /* pc_func skipped */ pc_release() /* fh_put only -- ACLs leaked */ The orphaned posix_acl is leaked for the lifetime of the server. Fix by adding nfsaclsvc_release_setacl() and nfs3svc_release_setacl(), which release both argp->acl_access and argp->acl_default in addition to fh_put(), and wiring them as pc_release for their respective SETACL procedures. pc_release runs on every path svc_process() takes after decode, including decode failure, so the posix_acl_release() pairs are removed from the proc functions' out: labels to keep ownership in one place. This matches the existing release_getacl() pattern used by the sibling GETACL procedures.

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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