GHSA-vmwr-mc7x-5vc3 is a medium-severity (CVSS 5.9) CWE-776 vulnerability in rexml. A fix is available for rexml — see the affected versions and patch details below.
REXML denial of service vulnerability
Exploitation Status
No confirmed exploitation observed yet
- 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-vmwr-mc7x-5vc3.
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.
How urgent is this, really
GHSA-vmwr-mc7x-5vc3 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 3.3.6 has a DoS vulnerability when it parses an XML that has many deep elements that have same local name attributes.
If you need to parse untrusted XMLs with tree parser API like REXML::Document.new, you may be impacted to this vulnerability. If you use other parser APIs such as stream parser API and SAX2 parser API, this vulnerability is not affected.
Patches
The REXML gem 3.3.6 or later include the patch to fix the vulnerability.
Workarounds
Don't parse untrusted XMLs with tree parser API.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rexml | all versions | 3.3.6bundle update rexml --conservative |
Detection & 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 3.3.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vmwr-mc7x-5vc3 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-vmwr-mc7x-5vc3 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-vmwr-mc7x-5vc3. 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.
| 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-vmwr-mc7x-5vc3 in your dependencies?
O3 Security finds GHSA-vmwr-mc7x-5vc3 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.