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NVD / CVE Program· CNA Linux

CVE-2025-40049: Squashfs: fix uninit-value in squashfs_get_parent

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: 0.22% (FIRST EPSS).
  • Fixed version: Linux Linux 1b3ccd0019132880c94bb00ca7088c1749308f82, 382a47fae449e554ef1e8c198667fd2f3270b945, 61d38b5ce2782bff3cacaacbb8164087a73ed1a5; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-2.

Low priority for now. Upgrade to Linux Linux 1b3ccd0019132880c94bb00ca7088c1749308f82, 382a47fae449e554ef1e8c198667fd2f3270b945, 61d38b5ce2782bff3cacaacbb8164087a73ed1a5; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-2 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: Squashfs: fix uninit-value in squashfs_get_parent Syzkaller reports a "KMSAN: uninit-value in squashfs_get_parent" bug. This is caused by open_by_handle_at() being called with a file handle containing an invalid parent inode number. In particular the inode number is that of a symbolic link, rather than a directory. Squashfs_get_parent() gets called with that symbolic link inode, and accesses the parent member field. unsigned int parent_ino = squashfs_i(inode)->parent; Because non-directory inodes in Squashfs do not have a parent value, this is uninitialised, and this causes an uninitialised value access. The fix is to initialise parent with the invalid inode 0, which will cause an EINVAL error to be returned. Regular inodes used to share the parent field with the block_list_start field. This is removed in this commit to enable the parent field to contain the invalid inode number 0.

—No exploit Fix available
Published
Oct 28, 2025
Updated
Oct 19, 2026
EPSS
0.2% · 13th 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%

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Noroxi analysis

What does it mean in your environment?

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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.

—

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

    • 2.6.29affected
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before f81a5bc9e924ee1950e0dd82bd10749048390f6eaffected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before 382a47fae449e554ef1e8c198667fd2f3270b945affected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before 61d38b5ce2782bff3cacaacbb8164087a73ed1a5affected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before 81a2bca52d43fc9d9abf07408b91255131c5dc53affected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before c28b0ca029edf5d0558abcd76cb8c732706cd339affected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before 1b3ccd0019132880c94bb00ca7088c1749308f82affected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before 91b99db7a92e57ff48a96a1b10fddfd2547e7f53affected · git
    • 122601408d20c77704268f1dea9f9ce4abf997c2 and later · before 74058c0a9fc8b2b4d5f4a0ef7ee2cfa66a9e49cfaffected · git
    • before 2.6.29not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.158-16.1.158-1
Debian:13linuxbefore 6.12.57-16.12.57-1
Debian:14linuxbefore 6.17.6-16.17.6-1

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-2025-40047Oct 28, 2025 · io_uring/waitid: always prune wait queue entry in io_waitid_wait()
    31Monitor
  • ← EarlierCVE-2025-40048Oct 28, 2025 · uio_hv_generic: Let userspace take care of interrupt mask
    30Monitor
  • Later →CVE-2025-40050Oct 28, 2025 · bpf: Skip scalar adjustment for BPF_NEG if dst is a pointer
    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 Linux1b3ccd0019132880c94bb00ca7088c1749308f82Vendor (CNA)
Linux Linux382a47fae449e554ef1e8c198667fd2f3270b945Vendor (CNA)
Linux Linux61d38b5ce2782bff3cacaacbb8164087a73ed1a5Vendor (CNA)
Linux Linux74058c0a9fc8b2b4d5f4a0ef7ee2cfa66a9e49cfVendor (CNA)
Linux Linux81a2bca52d43fc9d9abf07408b91255131c5dc53Vendor (CNA)
Linux Linux91b99db7a92e57ff48a96a1b10fddfd2547e7f53Vendor (CNA)
Linux Linuxc28b0ca029edf5d0558abcd76cb8c732706cd339Vendor (CNA)
Linux Linuxf81a5bc9e924ee1950e0dd82bd10749048390f6eVendor (CNA)
azl3 kernel 6.6.104.2-4 on Azure Linux 3.06.6.112.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.158-1 · Debian:12Package 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

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✗ → ✓

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References

Show all references (7 more)

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

All records