4.3

CVE-2023-42453: fedoraproject fedora Improper Authorization

CVSS: 4.3v3.1MediumModified
AliasesGHSA-7565-cq32-vx2xPYSEC-2023-180UBUNTU-CVE-2023-42453
Published 26-09-2023Last modified 18-06-2025
Open JSON

Vulnerability summary

CVE-2023-42453 is a medium (CVSS 4.3) Improper Authorization vulnerability in fedoraproject fedora. EPSS estimates a 0.78% chance of exploitation in the next 30 days, higher than 55% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (NVD)
EPSS score
0.78%
0%100%
Low · +0.13 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2024:13270-1USN-7444-1

Timeline

  1. 26-09-2023
    PublishedVulnerability first disclosed.
  2. 18-06-2025
    Last modifiedVulnerability information updated.

Description

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.78%

Chance of exploitation in the next 30 days

Percentile

55%

Versus all other CVEs

30-day change

+0.13 pp

From 0.65% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.78%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • matrix-synapse< 1.93.0-1
Fedoraproject1 product
Matrix1 product
Matrix-org1 product
PyPI1 product
  • matrix-synapse≥ 0.34.0, < 1.93.0 | ≥ 1.34.0, < 1.93.0
Ubuntu1 product
  • matrix-synapseAll versions (No fix recorded) | < 1.53.0-1ubuntu0.1~esm2

6 vendors · 6 products

References

17 links
Show all 17 references