# Squashfs: check block offset is not negative

CVE record · `CVE-2026-90203`

- **Identifiers:** `CVE-2026-90203`
- **State:** Confirmed
- **Severity:** CVSS 7.1 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 17 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 17 Sept 2026, 16:07 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before b169185d5c672b989985c6c2e38cafab2548ba88` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before c2a126fca820ae74872da28de68dc74d4595dc4b` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before 95dadf366c117dcdca78a570e6832071deab1ecd` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before 3d2f0cb66c909ea2312cdef465165bb9a3ba2d84` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before bbb2218eb072b0a15dc063929200183bd23c2344` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before d0a3729d464fcf516416a41cf304c0c92126ee03` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe` (git)
  - affected: `f400e12656ab518be107febfe2315fb1eab5a342 to before e300eb5002925b29be803d2661af07266cfa267e` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.29`
  - unaffected: `before 2.6.29` (semver)
  - unaffected: `5.10.270 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.221 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.188 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.157 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.110 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.52 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.6 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 7.1 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0017, the 6th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 17 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-90203](https://www.cve.org/CVERecord?id=CVE-2026-90203)
- [NVD: CVE-2026-90203](https://nvd.nist.gov/vuln/detail/CVE-2026-90203)

### References from the CNA

- <https://git.kernel.org/stable/c/b169185d5c672b989985c6c2e38cafab2548ba88>
- <https://git.kernel.org/stable/c/c2a126fca820ae74872da28de68dc74d4595dc4b>
- <https://git.kernel.org/stable/c/95dadf366c117dcdca78a570e6832071deab1ecd>
- <https://git.kernel.org/stable/c/3d2f0cb66c909ea2312cdef465165bb9a3ba2d84>
- <https://git.kernel.org/stable/c/bbb2218eb072b0a15dc063929200183bd23c2344>
- <https://git.kernel.org/stable/c/d0a3729d464fcf516416a41cf304c0c92126ee03>
- <https://git.kernel.org/stable/c/e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe>
- <https://git.kernel.org/stable/c/e300eb5002925b29be803d2661af07266cfa267e>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-90203>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-90203/>. Everything for agents: <https://agentprime.io/llms.txt>.