CVE-2026-35391

Q: How do I fix CVE-2026-35391?

Upgrade webmail to 1.4.11 or later.

Q: Is CVE-2026-35391 being actively exploited?

Not that we know of. CVE-2026-35391 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.14% is the estimated probability that it will be exploited in the next 30 days. That is higher than 3% of all scored CVEs.

Q: How severe is CVE-2026-35391?

CVE-2026-35391 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-35391 affect?

Published advisories record a fix for webmail (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

HIGH

7.5

CVSS v3

NVD

Description

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the getClientIP() function in lib/admin/session.ts trusted the first (leftmost) entry of the X-Forwarded-For header, which is fully controlled by the client. An attacker could forge their source IP address to bypass IP-based rate limiting (enabling brute-force attacks against the admin login) or forge audit log entries (making malicious activity appear to originate from arbitrary IP addresses). This vulnerability is fixed in 1.4.11.

CWE-348

How to fix

Remediation Available

webmailNVD

Affected:< 1.4.11Fixed in:1.4.11CVE-2026-35391derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploit Intelligence

0.14%probability of exploitation in 30 days

3rdpercentile

Low risk: more likely to be exploited than 3% of all known CVEs.

References

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-348 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-59951	Critical	9.1	4.7%	-	-
CVE-2022-31813	Critical	9.8	3.3%	-	Fix
CVE-2024-45410	Critical	9.8	1.5%	-	Fix
CVE-2021-21373	High	7.5	1.2%	-	Fix
CVE-2021-21374	High	8.1	1.0%	-	Fix
CVE-2022-2255	High	7.5	0.7%	-	Fix

Common questions

How do I fix CVE-2026-35391?

Upgrade webmail to 1.4.11 or later.

Is CVE-2026-35391 being actively exploited?

Not that we know of. CVE-2026-35391 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.14% is the estimated probability that it will be exploited in the next 30 days. That is higher than 3% of all scored CVEs.

How severe is CVE-2026-35391?

CVE-2026-35391 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-35391 affect?

Published advisories record a fix for webmail (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-24.