CVE-2026-29138
Seppmail Secure Email Gateway ≤ 15.0.3
Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-29138 is a medium-severity LDAP Injection (CWE-90) vulnerability in Seppmail Secure Email Gateway. Its CVSS base score is 6.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 12th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-29138 is a vulnerability in SEPPmail Secure Email Gateway versions prior to 15.0.3. It enables attackers to use a specially crafted email address to claim another user's PGP signature as their own. The issue carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) and is linked to CWE-90.
The vulnerability can be exploited by any unauthenticated attacker accessible over the network, requiring low complexity and no user interaction. Successful exploitation results in high integrity impact, allowing the attacker to impersonate another user's PGP signature without affecting confidentiality or availability.
SEPPmail's release notes for version 15.0, available at https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure-1503, disclose the vulnerability and confirm that it is addressed in version 15.0.3. Security practitioners should update affected SEPPmail Secure Email Gateway installations to version 15.0.3 or later to mitigate the issue.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18156
Vulnerability Data
SEPPmail Secure Email Gateway before version 15.0.3 allows attackers with a specially crafted email address to claim another user's PGP signature as their own.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.6
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover LDAP injection flaws through static analysis or crafted test cases.
Input validation directly stops untrusted data from reaching an LDAP query builder without neutralization of special characters.
Secure engineering principles require safe query construction and escaping that structurally prevents LDAP injection.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input neutralization and query parameterization to prevent LDAP injection.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches LDAP injection via dynamic analysis or fuzzing, but does not prevent it at the source.
Secure development lifecycle mandates input validation and query construction practices that directly prevent LDAP injection.
Application security requirements include explicit rules for safe construction of directory queries, mitigating LDAP injection.
Secure coding standards require proper neutralization of LDAP special characters, directly eliminating this weakness.
Secure architecture principles encourage safe query interfaces but do not prescribe the specific coding controls needed for LDAP injection.
Information access restriction limits who can query LDAP but does not address how queries are built.