CVE-2020-26891

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2020-26891
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-26891.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2020-26891
Aliases
Downstream
Related
Published
2020-10-19T17:15:13.220Z
Modified
2026-07-09T10:21:01.967957Z
Severity
  • 6.1 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS Calculator
Summary
[none]
Details

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

Affected packages

Git / github.com/matrix-org/synapse

Affected ranges

Type
GIT
Repo
https://github.com/matrix-org/synapse
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
cd0f65d2c71ce8f6cadfa84a6eb6b882d97e36c0
Fixed
9b8a53c7b9e1a3ca5f46e417b9fa705f8bacb494
Database specific 
{
    "source": [
        "CPE_RANGE",
        "REFERENCES"
    ],
    "cpe": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.21.0"
        }
    ]
}

Affected versions

Other
hhs-1
hhs-2
hhs-3
hhs-5
hhs-6
hhs-7
hhs-8
v0.*
v0.10.0
v0.10.0-r1
v0.10.0-r2
v0.11.0
v0.11.0-r1
v0.11.0-r2
v0.11.1
v0.12.0
v0.13.1
v0.13.2
v0.13.3
v0.14.0
v0.16.0
v0.16.1
v0.16.1-r1
v0.17.0
v0.17.1
v0.17.2
v0.17.3
v0.18.0
v0.18.1
v0.18.2
v0.18.3
v0.18.4
v0.18.5
v0.2.0
v0.2.1
v0.2.1a
v0.2.2
v0.23.0-rc1
v0.23.0-rc2
v0.25.0-rc1
v0.28.0-rc1
v0.3.0
v0.3.3
v0.3.4
v0.32.0
v0.32.0rc1
v0.32.2
v0.4.1
v0.4.2
v0.5.0
v0.5.1
v0.5.2
v0.5.3
v0.5.3a
v0.5.3b
v0.5.3c
v0.5.4
v0.5.4a
v0.6.0
v0.6.0a
v0.6.0b
v0.6.1
v0.6.1a
v0.6.1b
v0.6.1c
v0.6.1d
v0.6.1e
v0.6.1f
v0.7.0
v0.7.0a
v0.7.0b
v0.7.0c
v0.7.0d
v0.7.0e
v0.7.0f
v0.7.1
v0.7.1-r1
v0.7.1-r2
v0.7.1-r3
v0.7.1-r4
v0.8.0
v0.8.1
v0.8.1-r1
v0.8.1-r2
v0.8.1-r3
v0.8.1-r4
v0.9.0
v0.9.0-r1
v0.9.0-r2
v0.9.0-r3
v0.9.0-r4
v0.9.0-r5
v0.9.1
v0.9.2
v0.9.2-r1
v0.9.2-r2
v0.9.3
v0.99.1rc1
v0.99.2rc1
v0.99.4rc1
v0.99.5.1.dev0
v1.*
v1.1.0rc1
v1.1.0rc2
v1.10.0rc1
v1.11.0rc1
v1.12.0rc1
v1.14.0rc1
v1.15.0rc1
v1.16.0rc1
v1.17.0rc1
v1.18.0rc1
v1.21.0
v1.21.0rc1
v1.21.0rc2
v1.21.0rc3
v1.21.1
v1.3.0rc1
v1.4.0rc1
v1.5.0rc1
v1.6.0rc1
v1.8.0rc1
v1.9.0.dev1
v1.9.0.dev2
v1.9.0rc1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-26891.json"