How severe is GHSA-2j26-frm8-cmj9?

No CVSS score has been assigned to GHSA-2j26-frm8-cmj9 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-2j26-frm8-cmj9?

GHSA-2j26-frm8-cmj9 affects the following packages: activesupport (RubyGems), activesupport (RubyGems), activesupport (RubyGems). Ecosystems affected: RubyGems.

How do I fix GHSA-2j26-frm8-cmj9?

Update activesupport to 8.1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2j26-frm8-cmj9 is resolved across your whole dependency graph.

How do I detect GHSA-2j26-frm8-cmj9 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for activesupport, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-2j26-frm8-cmj9 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-2j26-frm8-cmj9 actively exploited in the wild?

No public exploit code has been indexed for GHSA-2j26-frm8-cmj9 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-2j26-frm8-cmj9?

GHSA-2j26-frm8-cmj9 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-2j26-frm8-cmj9?

GHSA-2j26-frm8-cmj9 is classified as Uncontrolled Resource Consumption (CWE-400), CWE-770 (CWE-770). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-2j26-frm8-cmj9 published, and has it been updated?

GHSA-2j26-frm8-cmj9 was published on March 23, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

Not in CISA KEV

Rails Active Support has a possible DoS vulnerability in its number helpersGHSA-2j26-frm8-cmj9

Fix: rails/rails@19dbab5

GHSA-2j26-frm8-cmj9 is a Uncontrolled Resource Consumption vulnerability in activesupport. A fix is available for activesupport — see the affected versions and patch details below.

Also known asCVE-2026-33176

Published

Mar 23, 2026

Updated

Sep 10, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-2j26-frm8-cmj9.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk+0.02%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

💎activesupport💎activesupport💎activesupport

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Active Support number helpers accept strings containing scientific notation (e.g. 1e10000), which when converted to a string could be expanded 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.

Releases

The fixed releases are available at the normal locations.

Credit

This issue was responsibly reported by Hackerone researcher manun.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`activesupport`	≥ 8.1.0.beta1&&< 8.1.2.1	8.1.2.1`bundle update activesupport --conservative`
💎RubyGems	`activesupport`	≥ 8.0.0.beta1&&< 8.0.4.1	8.0.4.1`bundle update activesupport --conservative`
💎RubyGems	`activesupport`	all versions	7.2.3.1`bundle update activesupport --conservative`

Affected Products

1 product · 3 configurations

Application

railsrubyonrails

≥ 8.1.0 && < 8.1.2.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for activesupport, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update activesupport to 8.1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2j26-frm8-cmj9 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

This flaw is rated as Moderate by Red Hat. Successful exploitation of this vulnerability requires an attacker to reach the vulnerable code path within the Active Support library as used by the hosting application. Because this functionality is not typically exposed directly to unauthenticated users, an attacker would…

Workaround published by Red Hat

To mitigate this issue, applications that use Active Support number helpers to process untrusted input should implement strict input validation. This involves sanitizing or restricting the format and length of numerical strings before they are passed to Active Support, thereby preventing the `BigDecimal` component from expanding into extremely large decimal representations and consuming excessive resources.

Source: Red Hat security advisory for GHSA-2j26-frm8-cmj9 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Satellite 6.16 for RHEL 8	`rubygem-activesupport-0:6.1.7.8-2.el8sat`	RHSA-2026:14874
Red Hat Satellite 6.17 for RHEL 9	`rubygem-activesupport-0:7.0.8.7-2.el9sat`	RHSA-2026:14873
Red Hat Satellite 6.18 for RHEL 9	`rubygem-activesupport-0:7.0.8.7-2.el9sat`	RHSA-2026:14835

Frequently Asked Questions

### Impact Active Support number helpers accept strings containing scientific notation (e.g. `1e10000`), which when converted to a string could be expanded 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. ### Releases The fixed releases are available at the normal locations. ### Credit This issue was responsibly reported by Hackerone researcher [manun](https://hackerone.com/manun).

O3 Security · Impact-Aware SCA

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