GHSA-5866-49gr-22v4 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in rexml. A fix is available for rexml — see the affected versions and patch details below.
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-5866-49gr-22v4.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
rexmlReal-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
The REXML gem before 3.3.2 has a DoS vulnerability when it parses an XML that has many entity expansions with SAX2 or pull parser API.
If you need to parse untrusted XMLs with SAX2 or pull parser API, you may be impacted to this vulnerability.
Patches
The REXML gem 3.3.3 or later include the patch to fix the vulnerability.
Workarounds
Don't parse untrusted XMLs with SAX2 or pull parser API.
References
- https://www.ruby-lang.org/en/news/2008/08/23/dos-vulnerability-in-rexml/ : This is a similar vulnerability
- https://www.ruby-lang.org/en/news/2024/08/01/dos-rexml-cve-2024-41946/: An announce on www.ruby-lang.org
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rexml | all versions | 3.3.3bundle update rexml --conservative |
Affected Products
rexmlruby-langDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rexml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rexml to 3.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5866-49gr-22v4 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.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for GHSA-5866-49gr-22v4 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | ruby:3.3-8100020240906074654.489197e6 | RHSA-2024:6784 |
| Red Hat Enterprise Linux 8 | ruby:3.1-8100020250407112943.489197e6 | RHSA-2025:4063 |
| Red Hat Enterprise Linux 8 | pcs-0:0.10.18-2.el8_10.2 | RHSA-2024:6670 |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | pcs-0:0.10.12-6.el8_6.6 | RHSA-2024:6702 |
| Red Hat Enterprise Linux 8.8 Extended Update Support | pcs-0:0.10.15-4.el8_8.3 | RHSA-2024:6703 |
| Red Hat Enterprise Linux 9 | ruby:3.3-9040020240906110954.9 | RHSA-2024:6785 |
| Red Hat Enterprise Linux 9 | ruby:3.1-9050020250404144903.9 | RHSA-2025:4488 |
Frequently Asked Questions
Is GHSA-5866-49gr-22v4 in your dependencies?
Find it across RubyGems, including transitive dependencies.