How severe is CVE-2026-33427?

CVE-2026-33427 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 none, integrity high, and availability none.

Is CVE-2026-33427 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33427?

CVE-2026-33427 primarily affects Discourse. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-33427?

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-2026-33427 have an EU (EUVD) identifier?

Yes. CVE-2026-33427 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13910.

When was CVE-2026-33427 published?

CVE-2026-33427 was published on 2026-03-21 and last updated on 2026-06-17.

CVE-2026-33427

CVE-2026-33427 is a high-severity vulnerability in Discourse 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. The underlying weakness is classified as CWE-862.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 2.7
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13910
Weakness: CWE-862
Affected product: Discourse
Published: 2026-03-21
Last modified: 2026-06-17

Description

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an unauthenticated attacker can cause a legitimate Discourse authorization page to display an attacker-controlled domain, facilitating social engineering attacks against users. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Frequently asked questions

What is CVE-2026-33427?: Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an unauthenticated attacker can cause a legitimate Discourse authorization page to display an attacker-controlled domain, facilitating social engineering attacks against users. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.
How severe is CVE-2026-33427?: CVE-2026-33427 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 none, integrity high, and availability none.
Is CVE-2026-33427 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33427?: CVE-2026-33427 primarily affects Discourse. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-33427?: 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-2026-33427 have an EU (EUVD) identifier?: Yes. CVE-2026-33427 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13910.
When was CVE-2026-33427 published?: CVE-2026-33427 was published on 2026-03-21 and last updated on 2026-06-17.

References

https://github.com/discourse/discourse/security/advisories/GHSA-9vhg-2mx3-mqfr

Affected products (2)

cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*

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