How severe is CVE-2026-4338?

CVE-2026-4338 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-4338 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4338?

CVE-2026-4338 affects Automattic Activitypub. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4338?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-4338 have an EU (EUVD) identifier?

Yes. CVE-2026-4338 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20058.

When was CVE-2026-4338 published?

CVE-2026-4338 was published on 2026-04-08 and last updated on 2026-06-17.

CVE-2026-4338

CVE-2026-4338 is a high-severity vulnerability in Automattic Activitypub with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20058
Affected product: Automattic Activitypub
Published: 2026-04-08
Last modified: 2026-06-17

Description

The ActivityPub WordPress plugin before 8.0.2 does not properly filter posts to be displayed, allowed unauthenticated users to access drafts/scheduled/pending posts

Frequently asked questions

What is CVE-2026-4338?: The ActivityPub WordPress plugin before 8.0.2 does not properly filter posts to be displayed, allowed unauthenticated users to access drafts/scheduled/pending posts
How severe is CVE-2026-4338?: CVE-2026-4338 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-4338 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4338?: CVE-2026-4338 affects Automattic Activitypub. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4338?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-4338 have an EU (EUVD) identifier?: Yes. CVE-2026-4338 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20058.
When was CVE-2026-4338 published?: CVE-2026-4338 was published on 2026-04-08 and last updated on 2026-06-17.

References

https://wpscan.com/vulnerability/50f68395-72fc-4f99-8e6d-6aa90cc640b5/

Affected products (1)

cpe:2.3:a:automattic:activitypub:*:*:*:*:*:wordpress:*:*

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