# ubifs: fix out-of-bounds read in signature length check

CVE record · `CVE-2026-89720`

- **Identifiers:** `CVE-2026-89720`
- **State:** Confirmed
- **Severity:** CVSS 7.7 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 11 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 11 Sept 2026, 19:46 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: `817aa094842dfc3a6b98c9582d4a647827f66201 to before ab7405bd86331cc2dbc8201699d4adc33bea75e7` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before 11abc34698cb3172badf8aa12e623f1bac98bbd8` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before 8cc3da72cf57acb4b77442ea8cec48425dff7c06` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before 37a9d25a563f5f9103282954ce573c4a61321e7c` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before f76b79d6e42af20682495bccd22f72c7164b0018` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before a1dc246f98bb94233effa4fa3ec7bf84700bb7d1` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before 83e1aa9f5f906c9b1f4949d0521f0f950a159d96` (git)
  - affected: `817aa094842dfc3a6b98c9582d4a647827f66201 to before 95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.3`
  - unaffected: `before 5.3` (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: `6.12.109 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.50 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.4 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0019, the 8th 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 11 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89720](https://www.cve.org/CVERecord?id=CVE-2026-89720)
- [NVD: CVE-2026-89720](https://nvd.nist.gov/vuln/detail/CVE-2026-89720)

### References from the CNA

- <https://git.kernel.org/stable/c/ab7405bd86331cc2dbc8201699d4adc33bea75e7>
- <https://git.kernel.org/stable/c/11abc34698cb3172badf8aa12e623f1bac98bbd8>
- <https://git.kernel.org/stable/c/8cc3da72cf57acb4b77442ea8cec48425dff7c06>
- <https://git.kernel.org/stable/c/37a9d25a563f5f9103282954ce573c4a61321e7c>
- <https://git.kernel.org/stable/c/f76b79d6e42af20682495bccd22f72c7164b0018>
- <https://git.kernel.org/stable/c/a1dc246f98bb94233effa4fa3ec7bf84700bb7d1>
- <https://git.kernel.org/stable/c/83e1aa9f5f906c9b1f4949d0521f0f950a159d96>
- <https://git.kernel.org/stable/c/95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf>

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-2026-89720>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89720/>. Everything for agents: <https://agentprime.io/llms.txt>.