CVE-2026-39829

Summary

golang.org/x/crypto/ssh: Invoking pathological RSA/DSA parameters may cause DoS

Severity

high

CVSS

7.5

EPSS

0.5% (p39)

CWE

CWE-347

Also known as

GHSA-w879-237q-wc7r, GO-2026-5018

Published

2026-06-25

Updated

2026-06-25

Advisory details

The RSA and DSA public key parsers did not enforce size limits on key parameters. A crafted public key with an excessively large modulus or DSA parameter could cause several minutes of CPU consumption during signature verification. This could be triggered by unauthenticated clients during public key authentication. RSA moduli are now limited to 8192 bits, and DSA parameters are validated per FIPS 186-2.

References

• https://github.com/advisories/GHSA-w879-237q-wc7r
• https://nvd.nist.gov/vuln/detail/CVE-2026-39829
• https://go.dev/cl/781641
• https://go.dev/cl/781661
• https://go.dev/issue/79565
• https://groups.google.com/g/golang-announce/c/a082jnz-LvI
• https://pkg.go.dev/vuln/GO-2026-5018

Related advisories

• CVE-2026-46595 — critical · Go/golang.org/x/crypto/ssh
• CVE-2026-39834 — critical · Go/golang.org/x/crypto/ssh
• CVE-2026-39831 — critical · Go/golang.org/x/crypto/ssh
• CVE-2026-39830 — critical · Go/golang.org/x/crypto/ssh
• CVE-2026-46597 — high · Go/golang.org/x/crypto/ssh
• CVE-2026-39827 — medium · Go/golang.org/x/crypto/ssh
• CVE-2026-39835 — medium · Go/golang.org/x/crypto/ssh
• CVE-2026-39828 — medium · Go/golang.org/x/crypto/ssh

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