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CVE-2023-42453

15
FAUCET Score

CVE-2023-42453 describes a vulnerability in Synapse, the open-source Matrix homeserver, allowing authenticated users to forge read receipts for any event, even if they are not in the room. This medium-severity issue (CVSS 4.3) has a low attack complexity and impacts integrity by misleading users into believing events have been read. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability. Users are advised to upgrade to Synapse version 1.93.0 to mitigate this issue.

Impacted Technologies

VendorProductVersion(s)CPE
>= 1.34.0, < 1.93.0CPE matchmatch criteria
cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*
37CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
38CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

3.1LOW

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
1.6
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.65%
Probability of exploitation in next 30 days
EPSS Percentile
47.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0065 is in the 58th percentile among its peer group of 21,977 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: matrix-synapseFixed in: 1.93.0

Vendor Advisories (1)

pipGHSA-7565-cq32-vx2xmedium

matrix-synapse vulnerable to improper validation of receipts allows forged read receipts

Sep 26, 2023

References

github.com / matrix-org/synapse/pull/16327
Issue TrackingPatch
github.com / matrix-org/synapse/security/advisories/GHSA-7565-cq32-vx2x
Vendor Advisory
lists.fedoraproject.org / archives/list/[email protected]/message/2AFB2Y3S2VCPCN5P2XCZTG24MBMZ7DM4
Mailing ListRelease Notes
lists.fedoraproject.org / archives/list/[email protected]/message/65QPC55I4D27HIZP7H2NQ34EOXHPP4AO
Mailing ListRelease Notes
lists.fedoraproject.org / archives/list/[email protected]/message/N6P4QULVUE254WI7XF2LWWOGHCYVFXFY
security.gentoo.org / glsa/202401-12