Synology MailPlus Server flaws enable remote attacks
Multiple vulnerabilities in Synology MailPlus Server allow remote attackers to compromise data integrity and confidentiality or cause denial of service.
Sourcecert.ssi.gouv.fr — open the original
What to check
- Applies to
- The 3 CVEs named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- No exploitation in the wild and no public exploit is recorded for the CVEs named.
The French national cybersecurity agency CERT-FR has issued an advisory regarding multiple security vulnerabilities in Synology MailPlus Server. The flaws affect versions prior to 4.0.1-21663 for DSM 7.2.1 and 7.2.2, and versions prior to 4.0.1-31663 for DSM 7.3.
The vulnerabilities enable remote attackers to compromise the integrity and confidentiality of data, as well as trigger denial-of-service conditions. Three CVEs have been assigned to track these issues: CVE-2025-15660, CVE-2026-13135, and CVE-2026-13136. Organizations running affected versions of Synology MailPlus Server should apply the patches provided by the vendor immediately to remediate these security weaknesses.
Mentioned in this report
Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0819
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