CVE-2026-33176

Rails Active Support has a possible DoS vulnerability in its number helpers

HIGH
7.5
CVSS Score
Published: March 23, 2026 at 11:29 PM UTC
Updated: June 17, 2026 at 10:37 AM UTC
2 products affected across 2 vendorsRailsActive Support

Using activesupport by rails?

Get instant alerts when new vulnerabilities affect activesupport - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.5
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 7.2.3.18.0.0 ≤ v < 8.0.4.18.1.0 ≤ v < 8.1.2.1
v < 7.2.3.1v < 8.0.4.1v < 8.1.2.1
Affected range stops below 7.2.3.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 8.0.4.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 8.1.2.1, so it looks safe — our inference, not a vendor statement

References (7)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400CWE-770

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card