GHSA-hcg3-q754-cr77 is a high-severity (CVSS 7.5) CWE-770 vulnerability in golang.org/x/crypto. A fix is available for golang.org/x/crypto — see the affected versions and patch details below.
golang.org/x/crypto Vulnerable to Denial of Service (DoS) via Slow or Incomplete Key Exchange
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-hcg3-q754-cr77.
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-hcg3-q754-cr77 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
golang.org/x/cryptoReal-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
SSH servers which implement file transfer protocols are vulnerable to a denial of service attack from clients which complete the key exchange slowly, or not at all, causing pending content to be read into memory, but never transmitted.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | golang.org/x/crypto | all versions | 0.35.0go get golang.org/x/crypto@v0.35.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/crypto, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update golang.org/x/crypto to 0.35.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hcg3-q754-cr77 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-hcg3-q754-cr77 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-hcg3-q754-cr77. 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.
While this flaw affects both SSH clients and servers implemented with golang.org/x/crypto/ssh, realistically the flaw will only lead to a DoS when transferring large files, greatly reducing the likelihood of exploitation.
| Product | Fixed in | Advisory |
|---|---|---|
| gatekeeper 3.15 for RHEL 9 | gatekeeper/gatekeeper-operator-bundle:v3.15.4-1 | RHSA-2025:3053 |
| gatekeeper 3.17 for RHEL 9 | gatekeeper/gatekeeper-operator-bundle:v3.17.2-2 | RHSA-2025:3051 |
| gatekeeper 3.18 for RHEL 9 | gatekeeper/gatekeeper-operator-bundle:v3.18.0-1 | RHSA-2025:3052 |
| multicluster-globalhub 1.2 for RHEL 9 | multicluster-globalhub/multicluster-globalhub-agent-rhel9:v1.2.2-3 | RHSA-2025:3498 |
| multicluster-globalhub 1.3 for RHEL 9 | multicluster-globalhub/multicluster-globalhub-agent-rhel9:v1.3.3-5 | RHSA-2025:3863 |
| OADP-1.4-RHEL-9 | oadp/oadp-mustgather-rhel9:1.4.5-34 | RHSA-2025:11396 |
| Red Hat Advanced Cluster Management for Kubernetes 2.10 for RHEL 9 | rhacm2/acm-cluster-permission-rhel9:v2.10.8-8 | RHSA-2025:4502 |
| Red Hat Advanced Cluster Management for Kubernetes 2.11 for RHEL 9 | rhacm2/endpoint-monitoring-rhel9-operator:v2.11.7-13 | RHSA-2025:4666 |
Frequently Asked Questions
Is GHSA-hcg3-q754-cr77 in your dependencies?
O3 Security finds GHSA-hcg3-q754-cr77 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.