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CVE-2026-53397· NVD / CVE Program· CNA Linux

nfsd: fix posix_acl leak on SETACL decode failure

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.52% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 0853ac544c590880d797b04daa33fcb72b6be0e1, 136b416593f1349cf6f72c8e3d18f0f204ee8545, 1e96239fddcefacf6afe6c498357be68eacbcabc; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0853ac544c590880d797b04daa33fcb72b6be0e1, 136b416593f1349cf6f72c8e3d18f0f204ee8545, 1e96239fddcefacf6afe6c498357be68eacbcabc; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Oct 19, 2026
EPSS
0.5% · 43th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel2.6.13 and later · before 5.10.260
  • linux linux kernel5.11 and later · before 5.15.211
  • linux linux kernel5.16 and later · before 6.1.177
  • linux linux kernel6.2 and later · before 6.6.144
  • linux linux kernel6.7 and later · before 6.12.95
  • linux linux kernel6.13 and later · before 6.18.38
  • linux linux kernel6.19 and later · before 7.1.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.13affected
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before b2eb1ffd511d1b3c3e21122f97cbbccea411e277affected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before b94c4be77682aab06d65ca7296149e3bcfb37353affected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before 887f92ceccf3eacd5f2402db21254d66372fae00affected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before 1e96239fddcefacf6afe6c498357be68eacbcabcaffected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before bd69a825485168ef74e815ecb286754b570fdcc7affected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before 136b416593f1349cf6f72c8e3d18f0f204ee8545affected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before a5b42c1e4ff2befaa6b96f7cbf32174751eba083affected · git
    • a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and later · before 0853ac544c590880d797b04daa33fcb72b6be0e1affected · git
    • before 2.6.13not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.50.1.el10_26.12.0-211.50.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-53392Jul 19, 2026 · NFSv4/flexfiles: reject zero filehandle version count
    30Monitor
  • ← EarlierCVE-2026-53394Jul 19, 2026 · nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
    30Monitor
  • Later →CVE-2026-53398Jul 19, 2026 · NFSD: Fix SECINFO_NO_NAME decode error cleanup
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0853ac544c590880d797b04daa33fcb72b6be0e1Vendor (CNA)
Linux Linux136b416593f1349cf6f72c8e3d18f0f204ee8545Vendor (CNA)
Linux Linux1e96239fddcefacf6afe6c498357be68eacbcabcVendor (CNA)
Linux Linux887f92ceccf3eacd5f2402db21254d66372fae00Vendor (CNA)
Linux Linuxa5b42c1e4ff2befaa6b96f7cbf32174751eba083Vendor (CNA)
Linux Linuxb2eb1ffd511d1b3c3e21122f97cbbccea411e277Vendor (CNA)
Linux Linuxb94c4be77682aab06d65ca7296149e3bcfb37353Vendor (CNA)
Linux Linuxbd69a825485168ef74e815ecb286754b570fdcc7Vendor (CNA)
azl3 kernel 6.6.143.1-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.50.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.1.177-1 · Debian:12Package registry (OSV)
opensuse:kernel-source7.1.4-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.50.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+7

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-401 · Missing Release of Memory after Effective Lifetime

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records