CVE-2026-127121

high

Description

SOGo before 5.12.13 contains an improper cryptographic signature verification vulnerability that allows remote attackers to replace a victim's contact S/MIME certificate by sending a spoofed multipart/signed message with a mismatched signature and an impersonated From address. Attackers can deliver a crafted CMS signedData object containing their own self-signed certificate, which SOGo's UIxMailView stores on the contact card without validating signature authenticity or certificate identity, enabling subsequent encrypted communications to be decrypted with the attacker's private key.

References

https://www.vulncheck.com/advisories/sogo-before-s-mime-certificate-spoofing-via-uixmailview

https://github.com/Alinto/sogo/releases/tag/SOGo-5.12.13

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-124529

Details

Source: Mitre, NVD

Published: 2026-11-12

Updated: 2026-11-12

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N

Severity: High

CVSS v3

Base Score: 6.5

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

Severity: Medium

CVSS v4

Base Score: 7.1

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: High

EPSS

EPSS: 0.00142