CVE-2025-30355
CVSS v3
7.5
HIGH
EPSS Score
1.2 %
exploit probability, as of 2026-10-19
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Get an alert for each new CVE published for the software you run.
Affected and fixed versions
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Packages
- matrix-synapsePyPIall versions · fixed in 1.127.1
Description
Synapse is an open source Matrix homeserver implementation. A malicious server can craft events which, when received, prevent Synapse version up to 1.127.0 from federating with other servers. The vulnerability has been exploited in the wild and has been fixed in Synapse v1.127.1. No known workarounds are available.
Technical details
- Published
- 2025-03-27
Frequently asked questions
What is CVE-2025-30355?
Is CVE-2025-30355 actively exploited?
What is the CVSS score for CVE-2025-30355?
Hear about the next vulnerability in your software
CVE Watch matches each new CVE to the vendors and products you list (vendor and product, not the version) and puts it in your alerts with its KEV and EPSS status.
Already have an account? Open CVE WatchNo credit card required · No monthly cap on website lookups · 250 API requests/month
Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? CVE Watch alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.