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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98636: squashfs: Add dictionary size range check to prevent shift-out-of-bounds

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: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 0cb85377daaefb4ce5ce72975f2deb27ee0e0cad, 1f7745fb3580152ca902ef181b605f33cabfb1d0, 7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0cb85377daaefb4ce5ce72975f2deb27ee0e0cad, 1f7745fb3580152ca902ef181b605f33cabfb1d0, 7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1 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: Add dictionary size range check to prevent shift-out-of-bounds When an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size is 0) is mounted, and performs shift operations using dictionarysize, the shift exponent is -1, causing a shift-out-of-bounds. Detail as below: squashfs_comp_opts(msblk, buffer, length) squashfs_xz_comp_opts() if (comp_opts) n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1 if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + (1 << (n + 1))) <----shift-out-of-bounds Fix it by adding a dictionary size range check before the shift operation.

—No exploit Fix available
Published
Oct 18, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 7th 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 · 0.1%

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  • 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.

—

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

    • 2.6.39affected
    • ff750311d30acc9564ef577050794953eee59f01 and later · before b02948a23455f8190a53887b2d2c13ae1d360ceaaffected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before 9d9c5c218ea356a1d88765214ad2919605280ab1affected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before 7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1affected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before c68e0068a236f9a7dfc19720bdf11e5d80a85089affected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before 88c673a0bd233df44ca0020da82f4fd3876de27aaffected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before 0cb85377daaefb4ce5ce72975f2deb27ee0e0cadaffected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before e1ca4e3a380ef3e8f46ce006f1146392e3f32c98affected · git
    • ff750311d30acc9564ef577050794953eee59f01 and later · before 1f7745fb3580152ca902ef181b605f33cabfb1d0affected · git
    • before 2.6.39not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.9-17.2.9-1

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-2026-98634Oct 18, 2026 · scsi: sd_zbc: Reject disks with too many zones
    0Monitor
  • ← EarlierCVE-2026-98635Oct 18, 2026 · scsi: block: Fix zones_cond out-of-bounds write on zone report
    0Monitor
  • Later →CVE-2026-98637Oct 18, 2026 · KVM: arm64: Do not clear VM-wide SVE feature on vCPU init failure
    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 Linux0cb85377daaefb4ce5ce72975f2deb27ee0e0cadVendor (CNA)
Linux Linux1f7745fb3580152ca902ef181b605f33cabfb1d0Vendor (CNA)
Linux Linux7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1Vendor (CNA)
Linux Linux88c673a0bd233df44ca0020da82f4fd3876de27aVendor (CNA)
Linux Linux9d9c5c218ea356a1d88765214ad2919605280ab1Vendor (CNA)
Linux Linuxb02948a23455f8190a53887b2d2c13ae1d360ceaVendor (CNA)
Linux Linuxc68e0068a236f9a7dfc19720bdf11e5d80a85089Vendor (CNA)
Linux Linuxe1ca4e3a380ef3e8f46ce006f1146392e3f32c98Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.159.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 7, 2026+20 d
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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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. Exploit maturity— → none
  2. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records