CVE-2023-36459
Mastodon vulnerable to Cross-site Scripting through oEmbed preview cards
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 1.3 and prior to versions 3.5.9, 4.0.5, and 4.1.3, an attacker using carefully crafted oEmbed data can bypass the HTML sanitization performed by Mastodon and include arbitrary HTML in oEmbed preview cards. This introduces a vector for cross-site scripting (XSS) payloads that can be rendered in the user's browser when a preview card for a malicious link is clicked through. Versions 3.5.9, 4.0.5, and 4.1.3 contain a patch for this issue.
Timeline
ID reserved
By GitHub_M
- 15 days later
· 15 days later
Published
- 20 months later
· 20 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Critical9.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N |
| NVDNVD · Modified | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 1.2% · top 31% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.3.
Weakness
Affected products
References (6)
- https://github.com/mastodon/mastodon/security/advisories/GHSA-ccm4-vgcc-73hp (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/mastodon/mastodon/commit/6d8e0fae3e96f3cf4febe03fa7fcf5b95ff761b2 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/mastodon/mastodon/releases/tag/v3.5.9 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/mastodon/mastodon/releases/tag/v4.0.5 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/mastodon/mastodon/releases/tag/v4.1.3 (opens in a new tab)x_refsource_MISCx_transferred
- http://www.openwall.com/lists/oss-security/2023/07/06/5 (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-36459)Record last updated .