# netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read

CVE record · `CVE-2026-80603`

- **Identifiers:** `CVE-2026-80603`
- **State:** Confirmed
- **Severity:** CVSS 9.1 Critical
- **Critical:** Yes: CVSS 9+
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 28 Aug 2026
- **Updated:** 16 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 28 Aug 2026, 06:48 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 9.1: 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: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 437e0a3854b3a44ec15afa9ab88ec215adf3a2fd` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 2b70f61f569bb29acb380e6f616a1bbdee15668f` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 2393f0bd7a467ad475598f3a5b9de27ca36e3037` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before aff589556ed772cb1c0c2d7b4d91ec45c0c39416` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before eeef3b81f449560653662df2dde6f6fe247c5365` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.12`
  - unaffected: `before 2.6.12` (semver)
  - unaffected: `5.10.261 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.212 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.178 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.145 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.97 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.40 to 6.18.*, inclusive` (semver)
  - unaffected: `7.1.5 to 7.1.*, inclusive` (semver)
  - unaffected: `7.2 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0060, the 49th percentile, on 15 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 28 Aug 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-80603](https://www.cve.org/CVERecord?id=CVE-2026-80603)
- [NVD: CVE-2026-80603](https://nvd.nist.gov/vuln/detail/CVE-2026-80603)

### References from the CNA

- <https://git.kernel.org/stable/c/abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e>
- <https://git.kernel.org/stable/c/437e0a3854b3a44ec15afa9ab88ec215adf3a2fd>
- <https://git.kernel.org/stable/c/910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1>
- <https://git.kernel.org/stable/c/2b70f61f569bb29acb380e6f616a1bbdee15668f>
- <https://git.kernel.org/stable/c/2393f0bd7a467ad475598f3a5b9de27ca36e3037>
- <https://git.kernel.org/stable/c/aff589556ed772cb1c0c2d7b4d91ec45c0c39416>
- <https://git.kernel.org/stable/c/eeef3b81f449560653662df2dde6f6fe247c5365>
- <https://git.kernel.org/stable/c/ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a>

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-2026-80603>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-80603/>. Everything for agents: <https://agentprime.io/llms.txt>.