Vulnerability · Published Apr 6, 2026 · Assigned by GitHub_M
CVE-2026-35389Bulwark Webmail S/MIME signature verification accepted self-signed certificates
High 8.7
In plain English
A high-severity improper certificate validation in webmail from bulwarkmail. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Severity (CVSS 4.0)8.7High
Exploit odds (30 days)0.2%top 92.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| bulwarkmail | webmail | < 1.4.11 |
Weakness: CWE-295 · Vector: 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
References
- https://github.com/bulwarkmail/webmail/security/advisories/GHSA-v6w6-338p-p256 x_refsource_CONFIRM