CVE-2026-53950 @tryghost/activitypub: XSS in Ghost's ActivityPub client
An attacker can inject JavaScript into Ghost posts via a malicious ActivityPub server, potentially compromising user sessions or data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-53950?
CVE-2026-53950 is a high-severity cross-site scripting vulnerability in TryGhost Ghost, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
@tryghost/activitypub is Ghost’s social/federation client app. Prior to 3.1.0, the ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server. This vulnerability is fixed in 3.1.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-53950?
3 open source packages ship an affected version, including @tryghost/activitypub and ghost.
| Package | Affected | Fixed in |
|---|---|---|
@tryghost/activitypub npm | All versions | 3.1.0 |
@tryghost/activitypub npm | All versions | 3.1.0 |
ghost Bitnami | All versions | 3.1.0 |
How do I fix CVE-2026-53950?
Upgrade @tryghost/activitypub to 3.1.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-53950 being exploited?
There is no known exploitation of CVE-2026-53950 in the wild and no public exploit code.
Sources
Also known as BIT-ghost-2026-53950, GHSA-xpp7-93x6-v29m.