# isofs: fix out-of-bounds page array access on empty zisofs block

CVE record · `CVE-2026-89778`

- **Identifiers:** `CVE-2026-89778`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 16 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 16 Sept 2026, 08:48 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.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before 8b994ac5778a725982fd6a8a3afcaa068d4a93e3` (git)
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a` (git)
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before 85904076cece72ee3194646ad7ac8e6659d999aa` (git)
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before f03425dcbe04aec3c27b9917e97d7d23a2908dda` (git)
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before cd616aa0449a772a6956abf03358f0ff31720580` (git)
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before 9c6eace8d07e90f038c89eb3b756d65a7e259d48` (git)
  - affected: `59bc055211b8d266ab6089158058bf8268e02006 to before 68d4d3e78150c7ed7d1195af63ad1e6ace30c661` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.33`
  - unaffected: `before 2.6.33` (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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0070, the 53rd percentile, on 14 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 16 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89778](https://www.cve.org/CVERecord?id=CVE-2026-89778)
- [NVD: CVE-2026-89778](https://nvd.nist.gov/vuln/detail/CVE-2026-89778)

### References from the CNA

- <https://git.kernel.org/stable/c/8b994ac5778a725982fd6a8a3afcaa068d4a93e3>
- <https://git.kernel.org/stable/c/ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a>
- <https://git.kernel.org/stable/c/85904076cece72ee3194646ad7ac8e6659d999aa>
- <https://git.kernel.org/stable/c/f03425dcbe04aec3c27b9917e97d7d23a2908dda>
- <https://git.kernel.org/stable/c/cd616aa0449a772a6956abf03358f0ff31720580>
- <https://git.kernel.org/stable/c/9c6eace8d07e90f038c89eb3b756d65a7e259d48>
- <https://git.kernel.org/stable/c/68d4d3e78150c7ed7d1195af63ad1e6ace30c661>

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-2026-89778>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89778/>. Everything for agents: <https://agentprime.io/llms.txt>.