CVE-2023-42453

unknown

Published 2023-09-26 · Modified 2023-11-08

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CVSS v3

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

CVSS v4 NEW

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not yet in upstream

VIR risk

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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.

Predictions

Exploit likelihood

30%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

Debian Fixed 2 releases

Version	Status	Fixed in
sid	Fixed	`1.93.0-1`
forky	Fixed	`1.93.0-1`

Package impact

Ecosystem	Package	Vulnerable	Fixed
PyPI	matrix-synapse	`>=0.34.0,<1.93.0`	`1.93.0`
PyPI	matrix-synapse	`>=1.34.0,<1.93.0`	`1.93.0`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.