NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
🐍 PyPI
Not in CISA KEV

Synapse allows a a malformed invite to break the invitee's `/sync`GHSA-f3r3-h2mq-hx2h

GHSA-f3r3-h2mq-hx2h is a Improper Input Validation vulnerability in matrix-synapse. A fix is available for matrix-synapse — see the affected versions and patch details below.

Also known asCVE-2024-52815PYSEC-2026-1611
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-f3r3-h2mq-hx2h.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs47th percentile — riskier than 47% of all scored CVEsHighest risk
0.00%0.36%0.71%1.07%0.3%0.6%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected
🐍matrix-synapse

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Synapse versions before 1.120.1 fail to properly validate invites received over federation. This vulnerability allows a malicious server to send a specially crafted invite that disrupts the invited user's /sync functionality.

Patches

Synapse 1.120.1 rejects such invalid invites received over federation and restores the ability to sync for affected users.

Workarounds

Server administrators can disable federation from untrusted servers.

For more information

If you have any questions or comments about this advisory, please email us at security at element.io.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPImatrix-synapseall versions1.120.1pip install --upgrade 'matrix-synapse==1.120.1'

Affected Products

1 product · 1 configurations
Application
synapsematrix
< 1.120.1
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for matrix-synapse, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update matrix-synapse to 1.120.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f3r3-h2mq-hx2h is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Synapse versions before 1.120.1 fail to properly validate invites received over federation. This vulnerability allows a malicious server to send a specially crafted invite that disrupts the invited user's `/sync` functionality. ### Patches Synapse 1.120.1 rejects such invalid invites received over federation and restores the ability to sync for affected users. ### Workarounds Server administrators can disable federation from untrusted servers. ### For more information If you have any questions or comments about this advisory, please email us at [security at element.io](mailto
O3 Security · Impact-Aware SCA

Is GHSA-f3r3-h2mq-hx2h in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works
Synapse allows a a malformed invite to break the invitee's…