CVE-2026-39827 — x/crypto
MEDIUMCVE-2026-39827 is a medium-severity (CVSS 6.5) CWE-924 vulnerability in golang.org/x/crypto. A fix is available for golang.org/x/crypto — see the affected versions and patch details below.
Invoking memory leak when rejecting channels can lead to DoS in golang.org/x/crypto/ssh
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 CVE-2026-39827.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-39827 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 395,308 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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
An authenticated SSH client that repeatedly opened channels which were rejected by the server caused unbounded memory growth, eventually crashing the server process and affecting all connected users. Rejected channels are now properly removed from the connection's internal state and released for garbage collection.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | golang.org/x/crypto | all versions | 0.52.0go get golang.org/x/crypto@v0.52.0 |
Affected Products
cryptogolangDetection & 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 0.52.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39827 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.
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 |
|---|---|---|
| Cert Manager support for Red Hat OpenShift release 1.17 | cert-manager/jetstack-cert-manager-acmesolver-rhel9:1791371080 | RHSA-2026:82304 |
| Cert Manager support for Red Hat OpenShift release 1.17 | cert-manager/cert-manager-operator-rhel9:1791788287 | RHSA-2026:82322 |
| multicluster engine for Kubernetes 2.11 | multicluster-engine/hypershift-addon-rhel9-operator:1786912006 | RHSA-2026:57194 |
| OpenShift API for Data Protection 1.6 | oadp/oadp-velero-rhel9:1784058822 | RHSA-2026:43692 |
| Red Hat Hardened Images | golang1-26-main-1.26.8-0.1.hum1 | RHSA-2026:62391 |
| Red Hat Hardened Images | golang1-27-main-1.27.1-0.1.hum1 | RHSA-2026:66561 |
| Red Hat Openshift Data Foundation 4.22 | odf4/cephcsi-rhel9:1782932114 | RHSA-2026:37387 |
Frequently Asked Questions
Is CVE-2026-39827 in your dependencies?
Find it across Go, including transitive dependencies.