PT-2026-29880 · Unknown · Stalwart Mail Server+1

Richardweinberger · CVE-2026-34834 · Published 2026-04-02 · Updated 2026-04-03

Positive Technologies (AI Summary)

CVSS v4.0

8.7

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Bulwark Webmail versions prior to 1.4.10

Description Bulwark Webmail, a self-hosted webmail client for Stalwart Mail Server, had a security flaw in the verifyIdentity() function. This function incorrectly returned true when no session cookies were present, allowing unauthenticated attackers to bypass security checks. Attackers could access and modify user settings via the /api/settings endpoint by providing arbitrary headers.

Recommendations Update Bulwark Webmail to version 1.4.10 or later.

Exploit

Fix

Improper Authentication

Weakness Enumeration

CWE-287

Related Identifiers

CVE-2026-34834

GHSA-4356-876G-RFMH

Affected Products

Bulwark Webmail

Stalwart Mail Server

References · 6

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34834.json · Exploit
• https://github.com/bulwarkmail/webmail/security/advisories/GHSA-4356-876g-rfmh · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-34834 · Security Note
• https://osv.dev/vulnerability/CVE-2026-34834 · Vendor Advisory
• https://github.com/bulwarkmail/webmail/releases/tag/1.4.10 · Note
• https://twitter.com/CVEnew/status/2040128768778379731 · Twitter Post