CVE-2026-33169

Rails Active Support has a possible ReDoS vulnerability in number_to_delimited

Severity Score

6.9

*CVSS v4

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

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 versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and `gsub!` can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

Active Support es un conjunto de herramientas de bibliotecas de soporte y extensiones del núcleo de Ruby extraídas del framework Rails. 'NumberToDelimitedConverter' utiliza una expresión regular basada en lookahead con 'gsub!' para insertar delimitadores de millares. Antes de las versiones 8.1.2.1, 8.0.4.1 y 7.2.3.1, la interacción entre el grupo lookahead repetido y 'gsub!' puede producir una complejidad de tiempo cuadrática en cadenas de dígitos largas. Las versiones 8.1.2.1, 8.0.4.1 y 7.2.3.1 contienen un parche.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

None

System

Vulnerable | Subsequent

Confidentiality

None

Integrity

None

Availability

Low

None

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2026-03-17 CVE Reserved
2026-03-23 CVE Published
2026-03-24 CVE Updated
2026-03-29 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-400: Uncontrolled Resource Consumption
CWE-1333: Inefficient Regular Expression Complexity

CAPEC

References (7)

URL	Tag	Source
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	Release Notes

URL	Date	SRC

URL	Date	SRC
https://github.com/rails/rails/commit/29154f1097da13d48fdb3200760b3e3da66dcb11	2026-03-24
https://github.com/rails/rails/commit/b54a4b373c6f042cab6ee2033246b1c9ecc38974	2026-03-24
https://github.com/rails/rails/commit/ec1a0e215efd27a3b3911aae6df978a80f456a49	2026-03-24

URL	Date	SRC
https://github.com/rails/rails/security/advisories/GHSA-cg4j-q9v8-6v38	2026-03-24

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Rubyonrails Search vendor "Rubyonrails"		Rails Search vendor "Rubyonrails" for product "Rails"				< 7.2.3.1 Search vendor "Rubyonrails" for product "Rails" and version " < 7.2.3.1"		-		Affected
Rubyonrails Search vendor "Rubyonrails"		Rails Search vendor "Rubyonrails" for product "Rails"				>= 8.0.0 < 8.0.4.1 Search vendor "Rubyonrails" for product "Rails" and version " >= 8.0.0 < 8.0.4.1"		-		Affected
Rubyonrails Search vendor "Rubyonrails"		Rails Search vendor "Rubyonrails" for product "Rails"				>= 8.1.0 < 8.1.2.1 Search vendor "Rubyonrails" for product "Rails" and version " >= 8.1.0 < 8.1.2.1"		-		Affected