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high 7.5

CVE-2026-53395 json

nfsd: fix dead ACL conflict guard in nfsd4_create

published 3mo ago modified 2mo ago also EUVD-2026-45517

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix dead ACL conflict guard in nfsd4_create

nfsd4_create() steals create->cr_dpacl/cr_pacl into the local nfsd_attrs via the designated initializer, then immediately sets the source pointers to NULL. The subsequent conflict guard tests the already-nilled source fields, making it permanently dead code:

if (create->cr_acl) { if (create->cr_dpacl || create->cr_pacl) /* always false */

When a client encodes both FATTR4_WORD0_ACL and FATTR4_WORD2_POSIX_{DEFAULT,ACCESS}_ACL in the same CREATE fattr bitmap, nfsd4_acl_to_attr() overwrites attrs.na_pacl/na_dpacl without releasing the originals, leaking two posix_acl slab objects per request. Repeated requests cause unbounded slab exhaustion.

Fix by checking attrs.na_dpacl/na_pacl (the stolen values) instead of the nilled create->cr_dpacl/cr_pacl, matching the correct pattern already used in nfsd4_setattr().

Patch / fix

  • Linux Linux 7.1.3, 7.2
  • linux Debian 14 7.1.3-1

debian advisories DEBIAN-CVE-2026-53395

  • linux Ubuntu 26.04 LTS 7.0.0-31.31
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1011.11
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1006.7
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1013.13
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-raspi Ubuntu 26.04 LTS 7.0.0-1019.19
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-31.31.1

ubuntu advisories UBUNTU-CVE-2026-53395

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.1.4-1.1

opensuse advisories openSUSE-SU-2026:11339-1

Is CVE-2026-53395 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-53395 updated cvss 7.0

kernel: nfsd: fix dead ACL conflict guard in nfsd4_create

  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-264.9.1.el10_3, perf 6.12.0-264.9.1.el10_3, rtla 6.12.0-264.9.1.el10_3, python3-perf 6.12.0-264.9.1.el10_3, kernel-devel-matched 6.12.0-264.9.1.el10_3, kernel-64k-devel-matched 6.12.0-264.9.1.el10_3, +7 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-264.9.1.el10_3, kernel-64k 6.12.0-264.9.1.el10_3, kernel-core 6.12.0-264.9.1.el10_3, kernel-tools 6.12.0-264.9.1.el10_3, kernel-modules 6.12.0-264.9.1.el10_3, kernel-64k-core 6.12.0-264.9.1.el10_3, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-264.9.1.el10_3, kernel-debuginfo-common-s390x 6.12.0-264.9.1.el10_3, kernel-debuginfo-common-x86_64 6.12.0-264.9.1.el10_3, kernel-debuginfo-common-aarch64 6.12.0-264.9.1.el10_3, kernel-debuginfo-common-ppc64le 6.12.0-264.9.1.el10_3 Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-264.9.1.el10_3, kernel-rt-64k 6.12.0-264.9.1.el10_3, kernel-rt-core 6.12.0-264.9.1.el10_3, kernel-rt-modules 6.12.0-264.9.1.el10_3, kernel-rt-64k-core 6.12.0-264.9.1.el10_3, kernel-rt-debug-core 6.12.0-264.9.1.el10_3, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-264.9.1.el10_3, kernel-rt-core 6.12.0-264.9.1.el10_3, kernel-rt-modules 6.12.0-264.9.1.el10_3, kernel-rt-debug-core 6.12.0-264.9.1.el10_3, kernel-rt-modules-core 6.12.0-264.9.1.el10_3, kernel-rt-debug-modules 6.12.0-264.9.1.el10_3, +5 more
    fixed: vendor fix RHSA-2026:97040
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.