CVE-2026-39830

CRITICAL 9.1

Invoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/ssh

CVSS Score

9.1

EPSS Score

0.0%

EPSS Percentile

4th

A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded.

Vendor	golang.org/x/crypto
Product	golang.org/x/crypto/ssh
Published	May 22, 2026
Last Updated	May 22, 2026

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Affected Versions

golang.org/x/crypto / golang.org/x/crypto/ssh

0 < 0.52.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

go.dev: https://go.dev/issue/79564 groups.google.com: https://groups.google.com/g/golang-announce/c/a082jnz-LvI go.dev: https://go.dev/cl/781640 go.dev: https://go.dev/cl/781664 pkg.go.dev: https://pkg.go.dev/vuln/GO-2026-5017

Credits

NCC Group Cryptography Services, sponsored by Teleport