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NVD / CVE Program· CNA Linux

CVE-2025-21795: NFSD: fix hang in nfsd4_shutdown_callback

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.66% (FIRST EPSS); higher than 51.9% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 036ac2778f7b28885814c6fbc07e156ad1624d03, 23ad7797c74cd8f7f90617f1e59a8703e2b43908, 38d345f612503b850c2973e5a879f88e441b34d7.
  • Severity is disputed: the assigning authority (CNA) scores it 7.5, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 036ac2778f7b28885814c6fbc07e156ad1624d03, 23ad7797c74cd8f7f90617f1e59a8703e2b43908, 38d345f612503b850c2973e5a879f88e441b34d7 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 hang in nfsd4_shutdown_callback If nfs4_client is in courtesy state then there is no point to send the callback. This causes nfsd4_shutdown_callback to hang since cl_cb_inflight is not 0. This hang lasts about 15 minutes until TCP notifies NFSD that the connection was dropped. This patch modifies nfsd4_run_cb_work to skip the RPC call if nfs4_client is in courtesy state.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 27, 2025
Updated
Oct 15, 2026
EPSS
0.6% · 51th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CNA vs NVD score

NVD
5.5
CNA · Linux
7.5
2.0 point gap

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

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

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  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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 kernel5.10.220 and later · before 5.10.235
  • linux linux kernel5.15.154 and later · before 5.15.179
  • linux linux kernel5.19 and later · before 6.1.129
  • linux linux kernel6.2 and later · before 6.6.79
  • linux linux kernel6.7 and later · before 6.12.16
  • linux linux kernel6.13 and later · before 6.13.4
  • linux linux kernel6.14

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

    • 5.19affected
    • 67ef9e5fd737eab2495f2586df7e9ea30caa1b77 and later · before abed68027ea3ab893ac85cc46a00e2e64a324239affected · git
    • 26540b8940a2e21582afa61a6fb8af87310bac72 and later · before efa8a261c575f816c7e79a87aeb3ef8a0bd6b221affected · git
    • 66af25799940b26efd41ea6e648f75c41a48a2c2 and later · before 38d345f612503b850c2973e5a879f88e441b34d7affected · git
    • 66af25799940b26efd41ea6e648f75c41a48a2c2 and later · before 23ad7797c74cd8f7f90617f1e59a8703e2b43908affected · git
    • 66af25799940b26efd41ea6e648f75c41a48a2c2 and later · before cedfbb92cf97a6bff3d25633001d9c44442ee854affected · git
    • 66af25799940b26efd41ea6e648f75c41a48a2c2 and later · before e88d2451cd42e025465d6b51fd716a47b0b3800daffected · git
    • 66af25799940b26efd41ea6e648f75c41a48a2c2 and later · before 036ac2778f7b28885814c6fbc07e156ad1624d03affected · git
    • 5.10.220 and later · before 5.10.235affected · semver
    • 5.15.154 and later · before 5.15.179affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.129-16.1.129-1
Debian:13linuxbefore 6.12.16-16.12.16-1
Red Hat:rhel_eus:9.6::appstreamkernel-64k-debug-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-64k-debug-develbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-64k-debug-devel-matchedbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-64k-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-64k-develbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-64k-devel-matchedbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debug-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debug-develbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debug-devel-matchedbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debuginfo-common-aarch64before 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debuginfo-common-ppc64lebefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debuginfo-common-s390xbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-debuginfo-common-x86_64before 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-develbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-devel-matchedbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-docbefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-rt-64k-debug-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-rt-64k-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-rt-debug-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-rt-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6
Red Hat:rhel_eus:9.6::appstreamkernel-tools-debuginfobefore 0:5.14.0-570.79.1.el9_60:5.14.0-570.79.1.el9_6

+69

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • 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

Published before and after this one in the same product

  • ← EarlierCVE-2025-21790Feb 27, 2025 · vxlan: check vxlan_vnigroup_init() return value
    22Monitor
  • ← EarlierCVE-2025-21791Feb 27, 2025 · vrf: use RCU protection in l3mdev_l3_out()
    31Monitor
  • Later →CVE-2025-21796Feb 27, 2025 · nfsd: clear acl_access/acl_default after releasing them
    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 Linux036ac2778f7b28885814c6fbc07e156ad1624d03Vendor (CNA)
Linux Linux23ad7797c74cd8f7f90617f1e59a8703e2b43908Vendor (CNA)
Linux Linux38d345f612503b850c2973e5a879f88e441b34d7Vendor (CNA)
Linux Linux5.10.235Vendor (CNA)
Linux Linux5.15.179Vendor (CNA)
Linux Linuxabed68027ea3ab893ac85cc46a00e2e64a324239Vendor (CNA)
Linux Linuxcedfbb92cf97a6bff3d25633001d9c44442ee854Vendor (CNA)
Linux Linuxe88d2451cd42e025465d6b51fd716a47b0b3800dVendor (CNA)
Linux Linuxefa8a261c575f816c7e79a87aeb3ef8a0bd6b221Vendor (CNA)
debian:linux6.1.129-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-debuginfo0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-aarch640:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-ppc64le0:5.14.0-570.79.1.el9_6 · Red Hat:rhel_eus:9.6::appstreamPackage registry (OSV)

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.

No history yet (it accumulates with the daily EPSS job).

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).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • 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
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

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. Fix✗ → ✓

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

References

Show all references (13 more)

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

All records