Skip to content
Noroxi
CVE-2025-40237· NVD / CVE Program· CNA Linux

fs/notify: call exportfs_encode_fid with s_umount

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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).
  • Fixed version: Linux Linux 3f307a9f7a7a2822e38ac451b73e2244e7279496, 6.12.56, 6.6.115.

Low priority for now. Upgrade to Linux Linux 3f307a9f7a7a2822e38ac451b73e2244e7279496, 6.12.56, 6.6.115 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: fs/notify: call exportfs_encode_fid with s_umount Calling intotify_show_fdinfo() on fd watching an overlayfs inode, while the overlayfs is being unmounted, can lead to dereferencing NULL ptr. This issue was found by syzkaller. Race Condition Diagram: Thread 1 Thread 2 -------- -------- generic_shutdown_super() shrink_dcache_for_umount sb->s_root = NULL | | vfs_read() | inotify_fdinfo() | * inode get from mark * | show_mark_fhandle(m, inode) | exportfs_encode_fid(inode, ..) | ovl_encode_fh(inode, ..) | ovl_check_encode_origin(inode) | * deref i_sb->s_root * | | v fsnotify_sb_delete(sb) Which then leads to: [ 32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] [ 32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none) <snip registers, unreliable trace> [ 32.143353] Call Trace: [ 32.143732] ovl_encode_fh+0xd5/0x170 [ 32.144031] exportfs_encode_inode_fh+0x12f/0x300 [ 32.144425] show_mark_fhandle+0xbe/0x1f0 [ 32.145805] inotify_fdinfo+0x226/0x2d0 [ 32.146442] inotify_show_fdinfo+0x1c5/0x350 [ 32.147168] seq_show+0x530/0x6f0 [ 32.147449] seq_read_iter+0x503/0x12a0 [ 32.148419] seq_read+0x31f/0x410 [ 32.150714] vfs_read+0x1f0/0x9e0 [ 32.152297] ksys_read+0x125/0x240 IOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set to NULL in the unmount path. Fix it by protecting calling exportfs_encode_fid() from show_mark_fhandle() with s_umount lock. This form of fix was suggested by Amir in [1]. [1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/

—No exploit Fix available
Published
Dec 4, 2025
Updated
Oct 19, 2026
EPSS
0.2% · 9th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-40237

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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.

We use this product, ask for help

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.

—

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

    • 6.13affected
    • a1a541fbfa7e97c1100144db34b57553d7164ce5 and later · before 950b604384fd75d62e860bec7135b2b62eb4d508affected · git
    • f0c0ac84de17c37e6e84da65fb920f91dada55ad and later · before bc1c6b803e14ea2b8f7e33b7164013f666ceb656affected · git
    • 3c7c90274ae339e1ad443c9be1c67a20b80b9c76 and later · before 3f307a9f7a7a2822e38ac451b73e2244e7279496affected · git
    • c45beebfde34aa71afbc48b2c54cdda623515037 and later · before d1894bc542becb0fda61e7e513b09523cab44030affected · git
    • c45beebfde34aa71afbc48b2c54cdda623515037 and later · before a7c4bb43bfdc2b9f06ee9d036028ed13a83df42aaffected · git
    • 6.6.72 and later · before 6.6.73affected · semver
    • 6.6.74 and later · before 6.6.115affected · semver
    • 6.12.10 and later · before 6.12.56affected · semver
    • before 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 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40235Dec 4, 2025 · btrfs: directly free partially initialized fs_info in btrfs_check_leaked_roots()
    0Monitor
  • ← EarlierCVE-2025-40236Dec 4, 2025 · virtio-net: zero unused hash fields
    0Monitor
  • Later →CVE-2025-40238Dec 4, 2025 · net/mlx5: Fix IPsec cleanup over MPV device
    0Monitor

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 Linux3f307a9f7a7a2822e38ac451b73e2244e7279496Vendor (CNA)
Linux Linux6.12.56Vendor (CNA)
Linux Linux6.6.115Vendor (CNA)
Linux Linux6.6.73Vendor (CNA)
Linux Linux950b604384fd75d62e860bec7135b2b62eb4d508Vendor (CNA)
Linux Linuxa7c4bb43bfdc2b9f06ee9d036028ed13a83df42aVendor (CNA)
Linux Linuxbc1c6b803e14ea2b8f7e33b7164013f666ceb656Vendor (CNA)
Linux Linuxd1894bc542becb0fda61e7e513b09523cab44030Vendor (CNA)
almalinux:kernel6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.39.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.12.57-1 · Debian:13Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+4

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).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

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 (4 more)

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

All records