rubygems.org MFA Bypass through password reset function could allow account takeover

published 2024-01-12 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-19280

cvss: 4.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits: 0; none known

Rubygems.org is the Ruby community's gem hosting service. Rubygems.org users with MFA enabled would normally be protected from account takeover in the case of email account takeover. However, a workaround on the forgotten password form allows an attacker to bypass the MFA requirement and takeover the account. This vulnerability has been patched in commit 0b3272a.

Patch / fix

fixed in 1 links 2

rubygems rubygems.org 2024-01-08

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-21654 updated 2026-11-05 cvss 4.8

rubygems: MFA bypass through password reset function could allow account takeover

Red Hat Enterprise Linux 6 rubygems
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 2 y ago (2024-10-24)

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.8	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

rubygems rubygems.org

Classification

Weakness

CWE-287 Improper Authentication
CWE-306 Missing Authentication for Critical Functionality

References

github.com /rubygems/rubygems.org/commit/0b3272ac17b45748ee0d1867c49867c7deb26565
patch
github.com /rubygems/rubygems.org/security/advisories/GHSA-4v23-vj8h-7jp2
patch, vendor-advisory

Sources

CVE List CVE-2024-21654
NVD CVE-2024-21654

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary