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NVD / CVE Program· CNA Linux

CVE-2025-21654: ovl: support encoding fid from inode with no alias

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: 0.20% (FIRST EPSS).
  • 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 3c7c90274ae339e1ad443c9be1c67a20b80b9c76, c45beebfde34aa71afbc48b2c54cdda623515037, f0c0ac84de17c37e6e84da65fb920f91dada55ad.

Low priority for now. Upgrade to Linux Linux 3c7c90274ae339e1ad443c9be1c67a20b80b9c76, c45beebfde34aa71afbc48b2c54cdda623515037, f0c0ac84de17c37e6e84da65fb920f91dada55ad 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: ovl: support encoding fid from inode with no alias Dmitry Safonov reported that a WARN_ON() assertion can be trigered by userspace when calling inotify_show_fdinfo() for an overlayfs watched inode, whose dentry aliases were discarded with drop_caches. The WARN_ON() assertion in inotify_show_fdinfo() was removed, because it is possible for encoding file handle to fail for other reason, but the impact of failing to encode an overlayfs file handle goes beyond this assertion. As shown in the LTP test case mentioned in the link below, failure to encode an overlayfs file handle from a non-aliased inode also leads to failure to report an fid with FAN_DELETE_SELF fanotify events. As Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails if it cannot find an alias for the inode, but this failure can be fixed. ovl_encode_fh() seldom uses the alias and in the case of non-decodable file handles, as is often the case with fanotify fid info, ovl_encode_fh() never needs to use the alias to encode a file handle. Defer finding an alias until it is actually needed so ovl_encode_fh() will not fail in the common case of FAN_DELETE_SELF fanotify events.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jan 19, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 10th percentile

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 · 0.2%

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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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 kernel6.6 and later · before 6.6.74
  • linux linux kernel6.7 and later · before 6.12.10
  • linux linux kernel6.13

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

    • 6.6affected
    • 16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 and later · before f0c0ac84de17c37e6e84da65fb920f91dada55adaffected · git
    • 16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 and later · before 3c7c90274ae339e1ad443c9be1c67a20b80b9c76affected · git
    • 16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 and later · before c45beebfde34aa71afbc48b2c54cdda623515037affected · git
    • before 6.6not affected · semver
    • 6.6.74 and later · up to and including 6.6.*not affected · semver
    • 6.12.10 and later · up to and including 6.12.*not affected · semver
    • 6.13 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.10-16.12.10-1

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-2025-21652Jan 19, 2025 · ipvlan: Fix use-after-free in ipvlan_get_iflink().
    31Monitor
  • ← EarlierCVE-2025-21653Jan 19, 2025 · net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute
    22Monitor
  • Later →CVE-2024-57904Jan 19, 2025 · iio: adc: at91: call input_free_device() on allocated iio_dev
    31Monitor

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 Linux3c7c90274ae339e1ad443c9be1c67a20b80b9c76Vendor (CNA)
Linux Linuxc45beebfde34aa71afbc48b2c54cdda623515037Vendor (CNA)
Linux Linuxf0c0ac84de17c37e6e84da65fb920f91dada55adVendor (CNA)
debian:linux6.12.10-1 · Debian:13Package 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.

  • CVE-2026-31739467 days apartcrypto: tegra - Add missing CRYPTO_ALG_ASYNC
    35Monitor
  • CVE-2026-52952521 days apartiommu: Fix WARN_ON in __iommu_group_set_domain_nofail() due to reset
    35Monitor
  • CVE-2025-39803239 days apartscsi: ufs: core: Remove WARN_ON_ONCE() call from ufshcd_uic_cmd_compl()
    31Monitor
  • CVE-2023-52621299 days apartbpf: Check rcu_read_lock_trace_held() before calling bpf map helpers
    31Monitor
  • CVE-2026-31398439 days apartmm/rmap: fix incorrect pte restoration for lazyfree folios
    31Monitor
  • CVE-2026-46117494 days apartRDMA/mana: Remove user triggerable WARN_ON() in mana_ib_create_qp_rss()
    31Monitor

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)

CWE-617 · Reachable Assertion

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 (2 more)

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

All records