BIT-ghost-2026-53950Published

@tryghost/activitypub: XSS in Ghost's ActivityPub client

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-53950

Published

@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.

Source published: 24 Jun 2026 18:04:25 UTC
Source modified: 24 Jun 2026 18:49:55 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

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CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

euvd · EUVD-2026-39019

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Jun 24, 2026, 6:04:25 PM

dateUpdated: Jun 24, 2026, 6:49:55 PM

Source published: Jun 24, 2026, 6:04:25 PM (timezone not stated)
Source modified: Jun 24, 2026, 6:49:55 PM (timezone not stated)
Observed here: 7 Nov 2026 12:28:06 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

nvd · CVE-2026-53950

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-79

Original publisher date fields

published: 2026-06-24T19:17:12.713

lastModified: 2026-10-25T22:10:00.150

Source published: 24 Jun 2026 19:17:12 UTC
Source modified: 25 Oct 2026 22:10:00 UTC
Observed here: 27 Oct 2026 14:13:29 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

osv · GHSA-xpp7-93x6-v29m

Published

### Impact The ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server. ### Vulnerable Versions This vulnerability is present in the @tryghost/activitypub package up to v3.0.8. All prior versions are also affected. ### Patches @tryghost/activitypub v3.1.0 contains a fix for this issue and is also automatically fetched by Ghost. ### References Ghost thanks Brad Geesaman, Ghost Security for disclosing this vulnerability responsibly. ### For more information If you have any questions or comments about this advisory, email Ghost at [[email protected]](mailto:[email protected]).

Source published: 4 Aug 2026 21:54:01 UTC
Source modified: 4 Aug 2026 22:00:24 UTC
Observed here: 24 Oct 2026 13:17:17 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Publisher rating · HIGH