How severe is CVE-2022-39254?

CVE-2022-39254 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2022-39254 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-39254?

CVE-2022-39254 affects Matrix-nio Project Matrix-nio. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2022-39254?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2022-39254 published?

CVE-2022-39254 was published on 2022-09-29 and last updated on 2026-06-17.

CVE-2022-39254

CVE-2022-39254 is a high-severity vulnerability in Matrix-nio Project Matrix-nio with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 8.6)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Matrix-nio Project Matrix-nio
Published: 2022-09-29
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2022-39254?: 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.
How severe is CVE-2022-39254?: CVE-2022-39254 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2022-39254 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-39254?: CVE-2022-39254 affects Matrix-nio Project Matrix-nio. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-39254?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2022-39254 published?: CVE-2022-39254 was published on 2022-09-29 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:matrix-nio_project:matrix-nio:*:*:*:*:*:*:*:*

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