CVE-2022-39254

Name: CVE-2022-39254
Creator: NVD / NIST
Published: 2022-09-29T15:15:10.513+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.56%

Last modified Jun 17, 2026

CVE-2022-39254 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

Description

matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. Once they receive a forwarded room key, they accept it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.20 fixes the issue.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.56%

42.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Matrix-Nio Project	Matrix-Nio	< 0.20

References

https://github.com/poljar/matrix-nio/commit/b1cbf234a831daa160673defd596e6450e9c29f0Patch, Third Party Advisory
https://github.com/poljar/matrix-nio/security/advisories/GHSA-w4pr-4vjg-hffhThird Party Advisory
https://github.com/poljar/matrix-nio/commit/b1cbf234a831daa160673defd596e6450e9c29f0Patch, Third Party Advisory
https://github.com/poljar/matrix-nio/security/advisories/GHSA-w4pr-4vjg-hffhThird Party Advisory

Timeline

Published: Sep 29, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-39254?

How severe is CVE-2022-39254?

CVE-2022-39254 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2022-39254?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-39254?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST