Resource exhaustion in Rails Activesupport

CVE-2026-33169

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. `NumberToDelimitedConverter` uses a lookahead-based regular expression with `gsub!` to insert thousands delimiters. Prior to vers…

Vulnerability class: DoS (Denial of Service)

EPSS: 0.005 (39.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-33169?
CVE-2026-33169 is a medium-severity vulnerability in Rails Activesupport, classified under Uncontrolled Resource Consumption. CVSS score: 5.3/10. Published 2026-03-24.
How severe is CVE-2026-33169?
Medium severity. CVSS v3 base score is 5.3 out of 10.