Medium 6.6Published Mar 23, 2026

CVE-2026-33176Rails Active Support has a possible DoS vulnerability in its number helpers

Updated under an hour ago (Oct 26, 2026, 6:50 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for rails activesupport

Exploited in the last 30 days

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, Active Support number helpers accept strings containing scientific notation (e.g. `1e10000`), which `BigDecimal` expands into extremely large decimal representations. This can cause excessive memory allocation and CPU consumption when the expanded number is formatted, possibly resulting in a DoS vulnerability. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

CVSS: 6.6 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
Weakness (CWE): CWE-400, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Mar 24, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

rails activesupport rails:activesupport (from the name)	from 8.1.0.beta1, < 8.1.2.1; from 8.0.0.beta1, < 8.0.4.1; before 7.2.3.1	CNA record
rubyonrails rails rubyonrails:rails	before 7.2.3.1; from 8.0.0 before 8.0.4.1; from 8.1.0 before 8.1.2.1	NVD

References

References

https://github.com/rails/rails/security/advisories/GHSA-2j26-frm8-cmj9	x-refsource-confirm, vendor-advisory
https://github.com/rails/rails/commit/19dbab51ca086a657bb86458042bc44314916bcb	x-refsource-misc, patch
https://github.com/rails/rails/commit/ebd6be18120d1136511eb516338e27af25ac0a1a	x-refsource-misc, patch
https://github.com/rails/rails/commit/ee2c59e730e5b8faed502cd2c573109df093f856	x-refsource-misc, patch
https://github.com/rails/rails/releases/tag/v7.2.3.1	x-refsource-misc, release-notes
https://github.com/rails/rails/releases/tag/v8.0.4.1	x-refsource-misc, release-notes
https://github.com/rails/rails/releases/tag/v8.1.2.1	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.