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NVD / CVE Program· CNA Linux

CVE-2025-38415: Squashfs: check return result of sb_min_blocksize

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.21% (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 0aff95d9bc7fb5400ca8af507429c4b067bdb425, 295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282, 4f99357dadbf9c979ad737156ad4c37fadf7c56b; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1; azl3 kernel 6.6.96.1-1 on Azure Linux 3.0 6.6.96.1-1.

Low priority for now. Upgrade to Linux Linux 0aff95d9bc7fb5400ca8af507429c4b067bdb425, 295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282, 4f99357dadbf9c979ad737156ad4c37fadf7c56b; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1; azl3 kernel 6.6.96.1-1 on Azure Linux 3.0 6.6.96.1-1 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: check return result of sb_min_blocksize Syzkaller reports an "UBSAN: shift-out-of-bounds in squashfs_bio_read" bug. Syzkaller forks multiple processes which after mounting the Squashfs filesystem, issues an ioctl("/dev/loop0", LOOP_SET_BLOCK_SIZE, 0x8000). Now if this ioctl occurs at the same time another process is in the process of mounting a Squashfs filesystem on /dev/loop0, the failure occurs. When this happens the following code in squashfs_fill_super() fails. ---- msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); msblk->devblksize_log2 = ffz(~msblk->devblksize); ---- sb_min_blocksize() returns 0, which means msblk->devblksize is set to 0. As a result, ffz(~msblk->devblksize) returns 64, and msblk->devblksize_log2 is set to 64. This subsequently causes the UBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36 shift exponent 64 is too large for 64-bit type 'u64' (aka 'unsigned long long') This commit adds a check for a 0 return by sb_min_blocksize().

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 25, 2025
Updated
Jun 18, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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

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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.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel5.5 and later · before 5.10.239
  • linux linux kernel5.11 and later · before 5.15.186
  • linux linux kernel5.16 and later · before 6.1.142
  • linux linux kernel2.6.29 and later · before 5.4.295
  • linux linux kernel6.7 and later · before 6.12.34
  • linux linux kernel6.13 and later · before 6.15.3
  • linux linux kernel6.2 and later · before 6.6.94

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
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before db7096ea160e40d78c67fce52e7cc51bde049497affected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 549f9e3d7b60d53808c98b9fde49b4f46d0524a5affected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 5c51aa862cbeed2f3887f0382a2708956710bd68affected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 6abf6b78c6fb112eee495f5636ffcc350dd2ce25affected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 4f99357dadbf9c979ad737156ad4c37fadf7c56baffected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 0aff95d9bc7fb5400ca8af507429c4b067bdb425affected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282affected · git
    • 0aa666190509ffab81c202c5095a166be23961ac and later · before 734aa85390ea693bb7eaf2240623d41b03705c84affected · 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
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-124.35.1.el10_16.12.0-124.35.1.el10_1
AlmaLinux:10kernel-docbefore 6.12.0-124.35.1.el10_16.12.0-124.35.1.el10_1
AlmaLinux:8bpftoolbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.100.1.el8_104.18.0-553.100.1.el8_10
AlmaLinux:8kernel-rtbefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10
AlmaLinux:8kernel-rt-corebefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10
AlmaLinux:8kernel-rt-debugbefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10
AlmaLinux:8kernel-rt-debug-corebefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10
AlmaLinux:8kernel-rt-debug-develbefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10
AlmaLinux:8kernel-rt-debug-modulesbefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10
AlmaLinux:8kernel-rt-debug-modules-extrabefore 4.18.0-553.100.1.rt7.441.el8_104.18.0-553.100.1.rt7.441.el8_10

+96

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-2025-38411Jul 25, 2025 · netfs: Fix double put of request
    31Monitor
  • ← EarlierCVE-2025-38413Jul 25, 2025 · virtio-net: xsk: rx: fix the frame's length check
    22Monitor
  • Later →CVE-2025-38416Jul 25, 2025 · NFC: nci: uart: Set tty->disc_data only in success path
    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 Linux0aff95d9bc7fb5400ca8af507429c4b067bdb425Vendor (CNA)
Linux Linux295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282Vendor (CNA)
Linux Linux4f99357dadbf9c979ad737156ad4c37fadf7c56bVendor (CNA)
Linux Linux549f9e3d7b60d53808c98b9fde49b4f46d0524a5Vendor (CNA)
Linux Linux5c51aa862cbeed2f3887f0382a2708956710bd68Vendor (CNA)
Linux Linux6abf6b78c6fb112eee495f5636ffcc350dd2ce25Vendor (CNA)
Linux Linux734aa85390ea693bb7eaf2240623d41b03705c84Vendor (CNA)
Linux Linuxdb7096ea160e40d78c67fce52e7cc51bde049497Vendor (CNA)
azl3 kernel 6.6.92.2-2 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.96.1-1 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:bpftool4.18.0-553.100.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.100.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-core4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-core4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-devel4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules-extra4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-devel4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-modules4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-modules-extra4.18.0-553.100.1.rt7.441.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.1.147-1 · Debian:12Package registry (OSV)
red hat:kernel-rt0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-core0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-core0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-debuginfo0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-devel0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-kvm0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules0:4.18.0-553.100.1.rt7.441.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)

+7

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

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
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 (9 more)

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

All records