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Fencer Vulns
medium 5.0

CVE-2022-39335 json

Synapse does not apply enough checks to servers requesting auth events of events in a room

published 2023-05-24 3 y ago modified 2026-06-17 4 mo ago also GHSA-45cj-f97f-ggwv , PYSEC-2023-65 , EUVD-2023-0137

cvss
5.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. The Matrix Federation API allows remote homeservers to request the authorization events in a room. This is necessary so that a homeserver receiving some events can validate that those events are legitimate and permitted in their room. However, in versions of Synapse up to and including 1.68.0, a Synapse homeserver answering a query for authorization events does not sufficiently check that the requesting server should be able to access them. The issue was patched in Synapse 1.69.0. Homeserver administrators are advised to upgrade.

Patch / fix

  • pypi matrix-synapse 1.69.0
  • matrix synapse 1.69.0
  • matrix-synapse Ubuntu Pro 22.04 LTS 1.53.0-1ubuntu0.1~esm2

ubuntu advisories UBUNTU-CVE-2022-39335

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • synapse Alpine 3.18 1.70.1-r0
  • synapse Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 1.69.0-r0

alpine advisories ALPINE-CVE-2022-39335

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-39335 updated cvss 5.5

matrix-synapse: Synapse does not apply enough checks to servers requesting auth events of events in a room

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
21 mo ago

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.0 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 5.0 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
GitHub 3.1 5.0 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
pypi matrix-synapse
<1.69.0
1.69.0

Affected products

  • matrix-org synapse

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-862 Missing Authorization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.