CVE-2020-26891

AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth/*/fallback/web or /_matrix/client/unstable/auth/*/fallback/web Synapse endpoints.

CVSS v3 6.1 MEDIUM
CVSS v2.0 4.3 MEDIUM

6.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

4.3^/10

CVSS v2.0 : MEDIUM

Vector : AV:N/AC:M/Au:N/C:N/I:P/A:N

Exploitability : 8.6 / Impact : 2.9

Access Vector NETWORK

Access Complexity MEDIUM

Authentication NONE

Confidentiality Impact NONE

Integrity Impact PARTIAL

Availability Impact NONE

References

Link	Resource
https://github.com/matrix-org/synapse/pull/8444	Issue Tracking Patch Third Party Advisory
https://github.com/matrix-org/synapse/releases/tag/v1.21.2	Release Notes Third Party Advisory
https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq	Patch Third Party Advisory
https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory	Release Notes Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2020-10-19 17:15

Updated : 2023-12-10 13:41

NVD link : CVE-2020-26891

Mitre link : CVE-2020-26891

CVE.ORG link : CVE-2020-26891

JSON object : View

Products Affected

matrix

synapse

CWE

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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