# CVE-2026-121602: Solanum before commit 2ce64de Heap Buffer Overflow via JOIN and SJOIN

Status: published. Published: 2026-11-03. Updated: 2026-11-03.

Solanum before commit 2ce64de contains a heap-based buffer overflow vulnerability that allows a malicious linked server to corrupt memory by sending overlong channel names in JOIN or SJOIN messages. Attackers controlling a peer server can trigger strcpy and sprintf overflows in ms_join and ms_sjoin to crash the ircd or potentially achieve remote code execution.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/solanum-ircd/solanum/pull/551
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/solanum-ircd/solanum/commit/2ce64debf65e9710e9eea099ada93dbf6655b5ff

## Affected products and versions

- solanum-ircd / solanum (solanum-ircd/solanum): ≥ 0; < 2ce64debf65e9710e9eea099ada93dbf6655b5ff (affected, git). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.5 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N; source: CNA: VulnCheck

- CVSS 4.0: 8.5 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-122

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/solanum-ircd/solanum/pull/551 (CNA: VulnCheck; issue-tracking, patch)

- https://github.com/solanum-ircd/solanum/commit/2ce64debf65e9710e9eea099ada93dbf6655b5ff (CNA: VulnCheck; patch)

- https://github.com/solanum-ircd/solanum/blob/2ea1382e4262b212a91034258c466f0f6754cd61/modules/core/m_join.c#L507 (CNA: VulnCheck; technical-description)

- https://github.com/solanum-ircd/solanum/blob/2ea1382e4262b212a91034258c466f0f6754cd61/ircd/channel.c#L371-L385 (CNA: VulnCheck; technical-description)

- https://github.com/solanum-ircd/solanum (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/solanum-before-commit-2ce64de-heap-buffer-overflow-via-join-and-sjoin (CNA: VulnCheck; third-party-advisory)

- https://github.com/solanum-ircd/solanum (disclosure@vulncheck.com)

- https://github.com/solanum-ircd/solanum/blob/2ea1382e4262b212a91034258c466f0f6754cd61/ircd/channel.c#L371-L385 (disclosure@vulncheck.com)

- https://github.com/solanum-ircd/solanum/blob/2ea1382e4262b212a91034258c466f0f6754cd61/modules/core/m_join.c#L507 (disclosure@vulncheck.com)

- https://github.com/solanum-ircd/solanum/commit/2ce64debf65e9710e9eea099ada93dbf6655b5ff (disclosure@vulncheck.com)

- https://github.com/solanum-ircd/solanum/pull/551 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/solanum-before-commit-2ce64de-heap-buffer-overflow-via-join-and-sjoin (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-121602; retrieved 2026-11-03; source updated 2026-11-03

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121602; retrieved 2026-11-03; source updated 2026-11-03

Revision: b1b46281da707e70f02a4ad7e0943c46b35593d718c0a329e7bbe37c70d08dd2

Canonical: https://y2.dev/cve/CVE-2026-121602

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