CVE-2026-53394
nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
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.
INFO
Published Date :
July 19, 2026, 12:16 p.m.
Last Modified :
Aug. 17, 2026, 5:17 a.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Apply the kernel patch to fix the NFS openowner race.
- Ensure NFS clients use the latest stable kernel version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-53394.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-53394 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-53394
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-53394 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-53394 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': 'c9aefb2b5f11337c9202c5bd0c45d71198449718', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': '017a6150106b054cc84d1b0582d97bd3a74d4281', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': 'a10bf67fe06469a71a401f72f328237345d553c0', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': '57aee7a35bb12753057c5b65d72d1f46c0e95b07', 'versionType': 'git'}], 'programFiles': ['fs/nfsd/nfs4state.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.95', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.38', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.3', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/nfsd/nfs4state.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': 'c9aefb2b5f11337c9202c5bd0c45d71198449718', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': '017a6150106b054cc84d1b0582d97bd3a74d4281', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': 'a10bf67fe06469a71a401f72f328237345d553c0', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': '57aee7a35bb12753057c5b65d72d1f46c0e95b07', 'versionType': 'git'}], 'programFiles': ['fs/nfsd/nfs4state.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.95', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.38', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.3', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/nfsd/nfs4state.c'], 'defaultStatus': 'affected'}] -
Initial Analysis by [email protected]
Jul. 29, 2026
Action Type Old Value New Value Added CWE CWE-401 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.38 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.1.3 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.10 up to (excluding) 6.12.95 Added Reference Type kernel.org: https://git.kernel.org/stable/c/017a6150106b054cc84d1b0582d97bd3a74d4281 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/57aee7a35bb12753057c5b65d72d1f46c0e95b07 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/a10bf67fe06469a71a401f72f328237345d553c0 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/c9aefb2b5f11337c9202c5bd0c45d71198449718 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': 'c9aefb2b5f11337c9202c5bd0c45d71198449718', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': '017a6150106b054cc84d1b0582d97bd3a74d4281', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': 'a10bf67fe06469a71a401f72f328237345d553c0', 'versionType': 'git'}, {'status': 'affected', 'version': '23df17788c6212809848f836b10c4f85b16843a5', 'lessThan': '57aee7a35bb12753057c5b65d72d1f46c0e95b07', 'versionType': 'git'}], 'programFiles': ['fs/nfsd/nfs4state.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.95', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.38', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.3', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/nfsd/nfs4state.c'], 'defaultStatus': 'affected'}] Added 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. Added Reference https://git.kernel.org/stable/c/017a6150106b054cc84d1b0582d97bd3a74d4281 Added Reference https://git.kernel.org/stable/c/57aee7a35bb12753057c5b65d72d1f46c0e95b07 Added Reference https://git.kernel.org/stable/c/a10bf67fe06469a71a401f72f328237345d553c0 Added Reference https://git.kernel.org/stable/c/c9aefb2b5f11337c9202c5bd0c45d71198449718