CVE-2023-42453
published 2023-09-27CVE-2023-42453: 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…
PriorityP420medium4.3CVSS 3.1
AVNACLPRLUINSUCNILAN
EPSS
0.65%
47.0th percentile
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.
Affected
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | matrix-synapse | < matrix-synapse 1.93.0-1 (forky) | matrix-synapse 1.93.0-1 (forky) |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| matrix-org | synapse | — | — |
| matrix | synapse | >= 1.34.0 < 1.93.0 | 1.93.0 |
CVSS provenance
nvdv3.14.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
osv5.0MEDIUM
vendor_ubuntu5.0MEDIUM
vendor_debian3.1LOW
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OSV
matrix-synapse vulnerabilities
osv·2025-04-22·CVSS 5.0
CVE-2023-32683 [MEDIUM] matrix-synapse vulnerabilities
matrix-synapse vulnerabilities
It was discovered that Synapse network policies could be bypassed via
specially crafted URLs. An attacker could possibly use this issue to
bypass authentication mechanisms. (CVE-2023-32683)
It was discovered that Synapse exposed cached device information. An
attacker could possibly use this issue to gain access to sensitive
information. (CVE-2023-43796)
It was discovered that Synapse could be tricked into rejecting state
changes in rooms. An attacker could possibly use this issue to cause
Synapse to stop functioning properly, resulting in a denial of service.
This issue was only fixed in Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.
(CVE-2022-39374)
It was discovered that Synapse stored user credentials in a server's
database temporarily. An attacker could possi
OSV
CVE-2023-42453: Synapse is an open-source Matrix homeserver written and maintained by the Matrix
osv·2023-09-27·CVSS 4.3
CVE-2023-42453 [MEDIUM] CVE-2023-42453: Synapse is an open-source Matrix homeserver written and maintained by the Matrix
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.
GHSA
matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
ghsa·2023-09-26
CVE-2023-42453 [MEDIUM] CWE-285 matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
### Impact
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.
### Patches
https://github.com/matrix-org/synapse/pull/16327
### Workarounds
There is no workaround.
OSV
matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
osv·2023-09-26
CVE-2023-42453 [MEDIUM] matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
### Impact
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.
### Patches
https://github.com/matrix-org/synapse/pull/16327
### Workarounds
There is no workaround.
Ubuntu
Synapse vulnerabilities
vendor_ubuntu·2025-04-22·CVSS 5.0
CVE-2023-41335 [MEDIUM] Synapse vulnerabilities
Title: Synapse vulnerabilities
Summary: Several security issues were fixed in Synapse.
It was discovered that Synapse network policies could be bypassed via
specially crafted URLs. An attacker could possibly use this issue to
bypass authentication mechanisms. (CVE-2023-32683)
It was discovered that Synapse exposed cached device information. An
attacker could possibly use this issue to gain access to sensitive
information. (CVE-2023-43796)
It was discovered that Synapse could be tricked into rejecting state
changes in rooms. An attacker could possibly use this issue to cause
Synapse to stop functioning properly, resulting in a denial of service.
This issue was only fixed in Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.
(CVE-2022-39374)
It was discovered that Synapse stored user credentials in
Debian
CVE-2023-42453: matrix-synapse - Synapse is an open-source Matrix homeserver written and maintained by the Matrix...
vendor_debian·2023·CVSS 3.1
CVE-2023-42453 [LOW] CVE-2023-42453: matrix-synapse - Synapse is an open-source Matrix homeserver written and maintained by the Matrix...
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.
Scope: local
forky: resolved (fixed in 1.93.0-1)
sid: resolved (fixed in 1.93.0-1)
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://github.com/matrix-org/synapse/pull/16327https://github.com/matrix-org/synapse/security/advisories/GHSA-7565-cq32-vx2xhttps://lists.fedoraproject.org/archives/list/[email protected]/message/2AFB2Y3S2VCPCN5P2XCZTG24MBMZ7DM4/https://lists.fedoraproject.org/archives/list/[email protected]/message/65QPC55I4D27HIZP7H2NQ34EOXHPP4AO/https://lists.fedoraproject.org/archives/list/[email protected]/message/N6P4QULVUE254WI7XF2LWWOGHCYVFXFY/https://security.gentoo.org/glsa/202401-12https://github.com/matrix-org/synapse/pull/16327https://github.com/matrix-org/synapse/security/advisories/GHSA-7565-cq32-vx2xhttps://lists.fedoraproject.org/archives/list/[email protected]/message/2AFB2Y3S2VCPCN5P2XCZTG24MBMZ7DM4/https://lists.fedoraproject.org/archives/list/[email protected]/message/65QPC55I4D27HIZP7H2NQ34EOXHPP4AO/https://lists.fedoraproject.org/archives/list/[email protected]/message/N6P4QULVUE254WI7XF2LWWOGHCYVFXFY/https://security.gentoo.org/glsa/202401-12
2023-09-27
Published