Bug 2572632 (CVE-2026-127121)

Summary: CVE-2026-127121 sogo: SOGo: Unauthorized certificate replacement via improper signature verification
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in SOGo. This vulnerability can lead to information disclosure by allowing a remote attacker to replace a victim's saved contact certificate. By sending a spoofed, digitally signed email with an impersonated sender address, an attacker can deliver their own certificate, which the application saves to the address book without verifying signature authenticity or identity. Consequently, the attacker can decrypt future encrypted email communications intended for the impersonated contact.
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Description OSIDB Bzimport 2026-11-12 16:13:56 UTC 
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.