High severity · published Mar 23, 2026
CVE-2026-33176
Rails Active Support has a possible DoS vulnerability in its number helpers
7.5
CVSS
0.9%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 58% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
activesupport · rails
>= 8.1.0.beta1, < 8.1.2.1; >= 8.0.0.beta1, < 8.0.4.1; < 7.2.3.1 · source: vendor
RA
Rails · Rubyonrails
before 7.2.3.1; 8.0.0 before 8.0.4.1; 8.1.0 before 8.1.2.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33176
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33176
Patch
https://github.com/rails/rails/commit/19dbab51ca086a657bb86458042bc44314916bcb
Patch
https://github.com/rails/rails/commit/ebd6be18120d1136511eb516338e27af25ac0a1a
Patch
https://github.com/rails/rails/commit/ee2c59e730e5b8faed502cd2c573109df093f856
Release Notes
https://github.com/rails/rails/releases/tag/v7.2.3.1
Release Notes
https://github.com/rails/rails/releases/tag/v8.0.4.1
Release Notes
https://github.com/rails/rails/releases/tag/v8.1.2.1
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