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Fencer Vulns
high 7.5

CVE-2025-71090 json

nfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()

published 2026-01-13 9 mo ago modified 2026-08-05 3 mo ago also EUVD-2026-2246

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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

nfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()

nfsd4_add_rdaccess_to_wrdeleg() unconditionally overwrites fp->fi_fds[O_RDONLY] with a newly acquired nfsd_file. However, if the client already has a SHARE_ACCESS_READ open from a previous OPEN operation, this action overwrites the existing pointer without releasing its reference, orphaning the previous reference.

Additionally, the function originally stored the same nfsd_file pointer in both fp->fi_fds[O_RDONLY] and fp->fi_rdeleg_file with only a single reference. When put_deleg_file() runs, it clears fi_rdeleg_file and calls nfs4_file_put_access() to release the file.

However, nfs4_file_put_access() only releases fi_fds[O_RDONLY] when the fi_access[O_RDONLY] counter drops to zero. If another READ open exists on the file, the counter remains elevated and the nfsd_file reference from the delegation is never released. This potentially causes open conflicts on that file.

Then, on server shutdown, these leaks cause __nfsd_file_cache_purge() to encounter files with an elevated reference count that cannot be cleaned up, ultimately triggering a BUG() in kmem_cache_destroy() because there are still nfsd_file objects allocated in that cache.

Patch / fix

  • Linux Linux 6.18.4, 6.19
  • linux Debian 14 6.18.5-1

debian advisories DEBIAN-CVE-2025-71090

  • linux Ubuntu 25.10 6.17.0-29.29
  • linux-aws Ubuntu 25.10 6.17.0-1015.15
  • linux-gcp Ubuntu 25.10 6.17.0-1018.19
  • linux-azure Ubuntu 25.10 6.17.0-1015.15
  • linux-raspi Ubuntu 25.10 6.17.0-1017.17
  • linux-riscv Ubuntu 25.10 6.17.0-29.29.1
  • linux-oracle Ubuntu 25.10 6.17.0-1014.14
  • linux-aws-6.17 Ubuntu 24.04 LTS 6.17.0-1017.17~24.04.1

ubuntu advisories UBUNTU-CVE-2025-71090

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

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-2025-71090 updated cvss 5.5

kernel: nfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • 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

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns 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.