GHSA-xhr3-wf7j-h255 is a medium-severity (CVSS 5.1) vulnerability in github.com/gomarkdown/markdown. A fix is available for github.com/gomarkdown/markdown — see the affected versions and patch details below.
Infinite loop in github.com/gomarkdown/markdown
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-xhr3-wf7j-h255.
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-xhr3-wf7j-h255 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 379,145 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
github.com/gomarkdown/markdownReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
The package github.com/gomarkdown/markdown is a Go library for parsing Markdown text and rendering as HTML. Prior to pseudoversion v0.0.0-20240729232818-a2a9c4f, which corresponds with commit a2a9c4f76ef5a5c32108e36f7c47f8d310322252, there was a logical problem in the paragraph function of the parser/block.go file, which allowed a remote attacker to cause a denial of service (DoS) condition by providing a tailor-made input that caused an infinite loop, causing the program to hang and consume resources indefinitely. Submit a2a9c4f76ef5a5c32108e36f7c47f8d310322252 contains fixes to this problem.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gomarkdown/markdown | all versions | 0.0.0-20240729212818-a2a9c4f76ef5go get github.com/gomarkdown/markdown@v0.0.0-20240729212818-a2a9c4f76ef5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gomarkdown/markdown, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/gomarkdown/markdown to 0.0.0-20240729212818-a2a9c4f76ef5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xhr3-wf7j-h255 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-xhr3-wf7j-h255 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-xhr3-wf7j-h255. 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.
Mitigation for this issue is either not available or the currently available options don't 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-xhr3-wf7j-h255 (CC BY 4.0)
Frequently Asked Questions
Is GHSA-xhr3-wf7j-h255 in your dependencies?
O3 Security finds GHSA-xhr3-wf7j-h255 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.