Bug 1179186 (CVE-2020-26891) - VUL-0: CVE-2020-26891: matrix-synapse: XSS due to unsafe interpolation of the session GET parameter
Summary: VUL-0: CVE-2020-26891: matrix-synapse: XSS due to unsafe interpolation of the...
Status: RESOLVED FIXED
Alias: CVE-2020-26891
Product: openSUSE Distribution
Classification: openSUSE
Component: Security (show other bugs)
Version: Leap 15.1
Hardware: Other Other
: P3 - Medium : Normal (vote)
Target Milestone: ---
Assignee: Aleksa Sarai
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/269623/
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-11-25 09:45 UTC by Alexandros Toptsoglou
Modified: 2021-02-05 02:21 UTC (History)
1 user (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Alexandros Toptsoglou 2020-11-25 09:45:25 UTC 
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.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26891
http://people.canonical.com/~ubuntu-security/cve/2020/CVE-2020-26891.html
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26891
https://github.com/matrix-org/synapse/pull/8444
https://github.com/matrix-org/synapse/releases
https://github.com/matrix-org/synapse/releases/tag/v1.21.2
https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq
https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory
Comment 1 Aleksa Sarai 2021-02-05 02:21:47 UTC 
This has long since been fixed (we now ship a much newer version of Synapse).