OpenSlides is a free, Web-based presentation and assembly system for managing and projecting agenda, motions, and elections of assemblies. OpenSlides version 3.2, due to unsufficient user input validation and escaping, it is vulnerable to persistant cross-site scripting (XSS). In the web applications users can enter rich text in various places, e.g. for personal notes or in motions. These fields can be used to store arbitrary JavaScript Code that will be executed when other users read the respective text. An attacker could utilize this vulnerability be used to manipulate votes of other users, hijack the moderators session or simply disturb the meeting. The vulnerability was introduced with 6eae497abeab234418dfbd9d299e831eff86ed45 on 16.04.2020, which is first included in the 3.2 release. It has been patched in version 3.3 ( in commit f3809fc8a97ee305d721662a75f788f9e9d21938, merged in master on 20.11.2020).
CVE-2020-26280
This high-severity CVE scores 8.9 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.9
- EG Score
- 8.9(low)
- EPSS
- 61.9%
- KEV
- Not listed
Published
December 18, 2020
Last Modified
November 21, 2024
References (10)
- security-advisories@githubhttps://github.com/OpenSlides/OpenSlides/blob/master/CHANGELOG.rst#version-33-2020-12-18
- security-advisories@githubhttps://github.com/OpenSlides/OpenSlides/commit/f3809fc8a97ee305d721662a75f788f9e9d21938
- security-advisories@githubhttps://github.com/OpenSlides/OpenSlides/pull/5714
- security-advisories@githubhttps://github.com/OpenSlides/OpenSlides/security/advisories/GHSA-w5wr-98qm-jx92
- security-advisories@githubhttps://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-043.txt
- af854a3a-2127-422b-91ae-364da2661108https://github.com/OpenSlides/OpenSlides/blob/master/CHANGELOG.rst#version-33-2020-12-18
- af854a3a-2127-422b-91ae-364da2661108https://github.com/OpenSlides/OpenSlides/commit/f3809fc8a97ee305d721662a75f788f9e9d21938
- af854a3a-2127-422b-91ae-364da2661108https://github.com/OpenSlides/OpenSlides/pull/5714
- af854a3a-2127-422b-91ae-364da2661108https://github.com/OpenSlides/OpenSlides/security/advisories/GHSA-w5wr-98qm-jx92
- af854a3a-2127-422b-91ae-364da2661108https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-043.txt
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| openslides | 1.3-rc1 ... 3.2 (27 versions) | 3.3 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 40× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-12 05:44 UTCEPSS rescore
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- 2026-05-24 16:48 UTCEPSS rescore
- 2026-05-23 03:59 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
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