GHSA-2j26-frm8-cmj9 — activesupport
Fix: rails/rails@19dbab5GHSA-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.
Rails Active Support has a possible DoS vulnerability in its number helpers
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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
activesupport💎activesupport💎activesupportReal-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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | activesupport | ≥ 8.1.0.beta1&&< 8.1.2.1 | 8.1.2.1bundle update activesupport --conservative |
| 💎RubyGems | activesupport | ≥ 8.0.0.beta1&&< 8.0.4.1 | 8.0.4.1bundle update activesupport --conservative |
| 💎RubyGems | activesupport | all versions | 7.2.3.1bundle update activesupport --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
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
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-2j26-frm8-cmj9 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-2j26-frm8-cmj9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
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…
| 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
Is GHSA-2j26-frm8-cmj9 in your dependencies?
O3 Security finds GHSA-2j26-frm8-cmj9 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.