Synapse: Invalid device keys degrade federation functionality
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.138.3, 1.139.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
Synapse is an open source Matrix homeserver implementation. Lack of validation for device keys in Synapse before 1.138.3 and in Synapse 1.139.0 allow an attacker registered on the victim homeserver to degrade federation functionality, unpredictably breaking outbound federation to other homeservers. The issue is patched in Synapse 1.138.3, 1.138.4, 1.139.1, and 1.139.2. Note that even though 1.138.3 and 1.139.1 fix the vulnerability, they inadvertently introduced an unrelated regression. For this reason, the maintainers of Synapse recommend skipping these releases and upgrading straight to 1.138.4 and 1.139.2.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- element-hq synapse
fixed in 1.138.3
- matrix-synapsePyPI
fixed in 1.138.3
- matrix-synapsePyPI
From 1.139.0rc2 · fixed in 1.139.1
- matrix-synapsePyPI
fixed in 1.138.3; From 1.139.0rc2 · fixed in 1.139.1