CVE-2026-33868
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Summary
Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.8, 4.4.15, and 4.3.21, an unauthenticated Open Redirect vulnerability (CWE-601) exists in the /web/* route due to improper handling of URL-encoded path segments. An attacker can craft a specially encoded URL that causes the application to redirect users to an arbitrary external domain, enabling phishing attacks and potential OAuth credential theft. The issue occurs because URL-encoded slashes (%2F) bypass Rails path normalization and are interpreted as host-relative redirects. Versions 4.5.8, 4.4.15, and 4.3.21 patch the issue.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| mastodon | mastodon | >= 4.5.0, < 4.5.8 | affected |
| mastodon | mastodon | >= 4.4.0, < 4.4.15 | affected |
| mastodon | mastodon | < 4.3.21 | affected |
Weaknesses
- CWE-601: CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: no
- Technical Impact: partial
References
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