Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2023-42453 — fedora

🟢 CVSS 3.1 — Low ✅ No Known Exploit CWE-285 NVD
3.1
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: None.

Weakness class

CVE-2023-42453 is classified as CWE-285: Improper Authorization. A request is carried out without confirming that the caller is permitted to perform it on that specific resource.

Affected software

CVE-2023-42453 is recorded against 3 packages.

  • fedora
  • matrix-synapse (from 1.34.0 up to 1.93.0)
  • synapse (from 1.34.0 up to 1.93.0)

Timeline and source

Published on 27 September 2023 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
github.com
lists.fedoraproject.org
lists.fedoraproject.org
lists.fedoraproject.org
security.gentoo.org
github.com
github.com
lists.fedoraproject.org
lists.fedoraproject.org
lists.fedoraproject.org
security.gentoo.org

Other advisories for this package

fedora has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-285: Improper Authorization) in other software:

CVE-2023-42453 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity LOW
CVSS Score 3.1
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
CWE CWE-285
Public Exploit ✅ No
Source NVD
Published 2023-09-27
Updated 2026-08-20
Modified 2026-06-17

Affected Packages

Software From version Fixed in
fedora
matrix-synapse 1.34.0 1.93.0
synapse 1.34.0 1.93.0

References

Similar Threats

Free Vulnerability Check

Is your site affected by CVE-2023-42453?

BotEraser helps you identify potentially vulnerable plugins and themes by checking your installation against CVE-2023-42453 and other known CVE records.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesCVECVE 2023