CVE-2020-26891

CVSS V2 Medium 4.3 CVSS V3 Medium 6.1
Description
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.
Overview
  • CVE ID
  • CVE-2020-26891
  • Assigner
  • cve@mitre.org
  • Vulnerability Status
  • Analyzed
  • Published Version
  • 2020-10-19T17:15:13
  • Last Modified Date
  • 2020-10-26T21:30:56
Weakness Enumerations
CWE URL
CWE-79 http://cwe.mitre.org/data/definitions/79.html
CPE Configuration (Product)
CPE Vulnerable Operator Version Start Version End
cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* 1 OR 1.21.0
CVSS Version 2
  • Version
  • 2.0
  • Vector String
  • AV:N/AC:M/Au:N/C:N/I:P/A:N
  • Access Vector
  • NETWORK
  • Access Compatibility
  • MEDIUM
  • Authentication
  • NONE
  • Confidentiality Impact
  • NONE
  • Integrity Impact
  • PARTIAL
  • Availability Impact
  • NONE
  • Base Score
  • 4.3
  • Severity
  • MEDIUM
  • Exploitability Score
  • 8.6
  • Impact Score
  • 2.9
CVSS Version 3
  • Version
  • 3.1
  • Vector String
  • CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
  • Attack Vector
  • NETWORK
  • Attack Compatibility
  • LOW
  • Privileges Required
  • NONE
  • User Interaction
  • REQUIRED
  • Scope
  • CHANGED
  • Confidentiality Impact
  • LOW
  • Availability Impact
  • NONE
  • Base Score
  • 6.1
  • Base Severity
  • MEDIUM
  • Exploitability Score
  • 2.8
  • Impact Score
  • 2.7
References
Reference URL Reference Tags
https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory Release Notes Vendor Advisory
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
Sources
Source Name Source URL
NIST https://nvd.nist.gov/vuln/detail/CVE-2020-26891
MITRE https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26891
History
Created Old Value New Value Data Type Notes
2022-05-10 16:22:07 Added to TrackCVE
2022-12-05 00:24:03 2020-10-19T17:15Z 2020-10-19T17:15:13 CVE Published Date updated
2022-12-05 00:24:03 2020-10-26T21:30:56 CVE Modified Date updated
2022-12-05 00:24:03 Analyzed Vulnerability Status updated