CVE-2026-35389

Bulwark Webmail S/MIME signature verification accepted self-signed certificates

CVSS 8.7 HIGHEPSS 0.2%CWE-295

Vexday Risk Score

21Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 8.7EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

06 Apr 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, S/MIME signature verification did not validate the certificate trust chain (checkChain: false). Any email signed with a self-signed or untrusted certificate was displayed as having a valid signature. This vulnerability is fixed in 1.4.11.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Affected products

bulwarkmail · webmail

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References

https://github.com/bulwarkmail/webmail/security/advisories/GHSA-v6w6-338p-p256