How severe is CVE-2026-29140?

CVE-2026-29140 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-29140 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-29140?

CVE-2026-29140 affects Seppmail Secure Email Gateway. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-29140?

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

Does CVE-2026-29140 have an EU (EUVD) identifier?

Yes. CVE-2026-29140 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18160.

When was CVE-2026-29140 published?

CVE-2026-29140 was published on 2026-04-02 and last updated on 2026-06-17.

CVE-2026-29140

CVE-2026-29140 is a medium-severity vulnerability in Seppmail Secure Email Gateway with a CVSS 3.x base score of 5.3. 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-295.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 7.7
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18160
Weakness: CWE-295
Affected product: Seppmail Secure Email Gateway
Published: 2026-04-02
Last modified: 2026-06-17

Description

SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to cause attacker-controlled certificates to be used for future encryption to a victim by adding the certificates to S/MIME signatures.

Frequently asked questions

What is CVE-2026-29140?: SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to cause attacker-controlled certificates to be used for future encryption to a victim by adding the certificates to S/MIME signatures.
How severe is CVE-2026-29140?: CVE-2026-29140 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-29140 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-29140?: CVE-2026-29140 affects Seppmail Secure Email Gateway. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29140?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-29140 have an EU (EUVD) identifier?: Yes. CVE-2026-29140 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18160.
When was CVE-2026-29140 published?: CVE-2026-29140 was published on 2026-04-02 and last updated on 2026-06-17.

References

https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure-1503

Affected products (1)

cpe:2.3:a:seppmail:secure_email_gateway:*:*:*:*:*:*:*:*

More vulnerabilities in Seppmail Secure Email Gateway

CVE-2026-29139 — Critical (CVSS 9.8): SEPPmail Secure Email Gateway before version 15.0.3 allows account takeover by abusing GINA account initialization to…
CVE-2026-29143 — Critical (CVSS 9.1): SEPPmail Secure Email Gateway before version 15.0.3 does not properly authenticate the inner message of…
CVE-2026-29133 — Critical (CVSS 9.1): SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to upload PGP keys with UIDs that do not match…
CVE-2026-29138 — High (CVSS 7.5): SEPPmail Secure Email Gateway before version 15.0.3 allows attackers with a specially crafted email address to claim…
CVE-2026-29135 — High (CVSS 7.5): SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to craft a password-tag that bypasses subject…
CVE-2026-29134 — High (CVSS 7.5): SEPPmail Secure Email Gateway before version 15.0.3 allows an external user to modify GINA webdomain metadata and…

All CVEs affecting Seppmail Secure Email Gateway →

Other CWE-295 (Improper Certificate Validation) vulnerabilities

CVE-2026-4370 — Critical (CVSS 10.0): A vulnerability was identified in Juju from version 3.2.0 until 3.6.19 and from version 4.0 until 4.0.4, where the…
CVE-2026-30836 — Critical (CVSS 10.0): Step CA is an online certificate authority for secure, automated certificate management for DevOps. Versions 0.30.0-rc6…
CVE-2025-68121 — Critical (CVSS 10.0): During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between…
CVE-2022-20703 — Critical (CVSS 10.0): Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker…
CVE-2021-1471 — Critical (CVSS 9.9): Multiple vulnerabilities in Cisco Jabber for Windows, Cisco Jabber for MacOS, and Cisco Jabber for mobile platforms…
CVE-2026-20184 — Critical (CVSS 9.8): A vulnerability in the integration of single sign-on (SSO) with Control Hub in Cisco Webex Services could have allowed…

Browse all CWE-295 (Improper Certificate Validation) vulnerabilities →