Auth bypass in Forem

CVE-2026-48780

Forem is open source software for building communities. Prior to commit a2ab6d4, a maliciously crafted email address could allow an attacker to bypass domain allowlist or denylist restrictions and gain access to invite-only forem deployments. The issue is patched as of `a2ab6d4`. As a workaround, some SMTP servers and email delivery providers may drop or refuse to send maliciously crafted email addresses.

Vulnerability class: Broken Authentication

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (28.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-48780: held from 0.002 to 0.004.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002

Affected products

  • Forem — versions < a2ab6d4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-48780?
CVE-2026-48780 is a high-severity vulnerability in Forem, classified under Improper Authentication. CVSS score: 8.2/10. Published 2026-06-16.
How severe is CVE-2026-48780?
High severity. CVSS v3 base score is 8.2 out of 10.