CVE-2025-66622

Q: How do I fix CVE-2025-66622?

Upgrade matrix-rust-sdk to 0.16.0 or later.

Q: Is CVE-2025-66622 being actively exploited?

Not that we know of. CVE-2025-66622 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.40% is the estimated probability that it will be exploited in the next 30 days. That is higher than 33% of all scored CVEs.

Q: How severe is CVE-2025-66622?

CVE-2025-66622 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2025-66622 affect?

Published advisories record a fix for matrix-rust-sdk (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

HIGH

7.5

CVSS v3

NVD

Description

matrix-sdk-base is the base component to build a Matrix client library. Versions 0.14.1 and prior are unable to handle responses that include custom m.room.join_rules values due to a serialization bug. This can be exploited to cause a denial-of-service condition, if a user is invited to a room with non-standard join rules, the crate's sync process will stall, preventing further processing for all rooms. This is fixed in version 0.16.0.

CWE-755

How to fix

Remediation Available

matrix-rust-sdkNVD

Affected:< 0.16.0Fixed in:0.16.0CVE-2025-66622derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.40%probability of exploitation in 30 days

33rdpercentile

Low risk: more likely to be exploited than 33% of all known CVEs.

References

Patch3

Third-Party Advisory1

rustsec.org

Related Vulnerabilities

Other CWE-755 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-5638	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-7247	Critical	9.8	99%	KEV	Fix
CVE-2023-36933	High	7.5	72%	-	Fix
CVE-2019-14287	High	8.8	64%	-	Fix
CVE-2018-0934	High	7.5	61%	-	Fix
CVE-2019-12815	Critical	9.8	58%	-	Fix

Common questions

How do I fix CVE-2025-66622?

Upgrade matrix-rust-sdk to 0.16.0 or later.

Is CVE-2025-66622 being actively exploited?

Not that we know of. CVE-2025-66622 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.40% is the estimated probability that it will be exploited in the next 30 days. That is higher than 33% of all scored CVEs.

How severe is CVE-2025-66622?

CVE-2025-66622 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2025-66622 affect?

Published advisories record a fix for matrix-rust-sdk (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-17.