CVE-2026-53950High· 7.5▾ TwilightXSS in Ghost's ActivityPub client
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Aug 4.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.2%
0.2% → 0.4%
The ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server.
This vulnerability is present in the @tryghost/activitypub package up to v3.0.8. All prior versions are also affected.
@tryghost/activitypub v3.1.0 contains a fix for this issue and is also automatically fetched by Ghost.
Ghost thanks Brad Geesaman, Ghost Security for disclosing this vulnerability responsibly.
If you have any questions or comments about this advisory, email Ghost at [email protected].
@tryghost/activitypub < 3.1.0Upgrade to a patched release:
@tryghost/activitypub 3.1.0Connected by shared product, vendor, weakness, or advisory.
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