How severe is CVE-2026-34834?

CVE-2026-34834 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-34834 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34834?

CVE-2026-34834 affects Bulwarkmail Webmail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34834?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-34834 have an EU (EUVD) identifier?

Yes. CVE-2026-34834 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18531.

When was CVE-2026-34834 published?

CVE-2026-34834 was published on 2026-04-02 and last updated on 2026-06-17.

CVE-2026-34834

CVE-2026-34834 is a high-severity vulnerability in Bulwarkmail Webmail with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18531
Weakness: CWE-287
Affected product: Bulwarkmail Webmail
Published: 2026-04-02
Last modified: 2026-06-17

Description

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to version 1.4.10, the verifyIdentity() function contained logic that returned true if no session cookies were present. This allowed unauthenticated attackers to bypass security checks and access/modify user settings via the /api/settings endpoint by providing arbitrary headers. This issue has been patched in version 1.4.10.

Frequently asked questions

What is CVE-2026-34834?: Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to version 1.4.10, the verifyIdentity() function contained logic that returned true if no session cookies were present. This allowed unauthenticated attackers to bypass security checks and access/modify user settings via the /api/settings endpoint by providing arbitrary headers. This issue has been patched in version 1.4.10.
How severe is CVE-2026-34834?: CVE-2026-34834 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-34834 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34834?: CVE-2026-34834 affects Bulwarkmail Webmail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34834?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-34834 have an EU (EUVD) identifier?: Yes. CVE-2026-34834 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18531.
When was CVE-2026-34834 published?: CVE-2026-34834 was published on 2026-04-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:bulwarkmail:webmail:*:*:*:*:*:*:*:*

More vulnerabilities in Bulwarkmail Webmail

CVE-2026-35391 — High (CVSS 7.5): Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the getClientIP() function…
CVE-2026-35389 — High (CVSS 7.5): Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, S/MIME signature…
CVE-2026-34833 — High (CVSS 7.5): Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to version 1.4.10, the GET…
CVE-2026-35390 — Medium (CVSS 5.4): Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the reverse proxy (proxy.ts)…

All CVEs affecting Bulwarkmail Webmail →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →