How severe is CVE-2026-35390?

CVE-2026-35390 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-35390 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-35390?

CVE-2026-35390 affects Bulwarkmail Webmail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-35390?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-35390 have an EU (EUVD) identifier?

Yes. CVE-2026-35390 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19479.

When was CVE-2026-35390 published?

CVE-2026-35390 was published on 2026-04-06 and last updated on 2026-06-17.

CVE-2026-35390

CVE-2026-35390 is a medium-severity vulnerability in Bulwarkmail Webmail with a CVSS 3.x base score of 5.4. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 5.3
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-19479
Weakness: CWE-79
Affected product: Bulwarkmail Webmail
Published: 2026-04-06
Last modified: 2026-06-17

Description

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the reverse proxy (proxy.ts) set the Content-Security-Policy-Report-Only header instead of the enforcing Content-Security-Policy header. This means cross-site scripting (XSS) attacks were logged but not blocked. Any user who could inject script content (e.g., via crafted email HTML) could execute arbitrary JavaScript in the context of the application, potentially stealing session tokens or performing actions on behalf of the user. This vulnerability is fixed in 1.4.11.

Frequently asked questions

What is CVE-2026-35390?: Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the reverse proxy (proxy.ts) set the Content-Security-Policy-Report-Only header instead of the enforcing Content-Security-Policy header. This means cross-site scripting (XSS) attacks were logged but not blocked. Any user who could inject script content (e.g., via crafted email HTML) could execute arbitrary JavaScript in the context of the application, potentially stealing session tokens or performing actions on behalf of the user. This vulnerability is fixed in 1.4.11.
How severe is CVE-2026-35390?: CVE-2026-35390 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-35390 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-35390?: CVE-2026-35390 affects Bulwarkmail Webmail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-35390?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-35390 have an EU (EUVD) identifier?: Yes. CVE-2026-35390 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19479.
When was CVE-2026-35390 published?: CVE-2026-35390 was published on 2026-04-06 and last updated on 2026-06-17.

References

https://github.com/bulwarkmail/webmail/security/advisories/GHSA-6q52-98cr-qx65

Affected products (1)

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

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