CVE-2026-39829 — Invoking pathological RSA/DSA parameters may cause DoS in golang.org/x/crypto/ssh

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
golang.org/x/crypto / golang.org/x/crypto/ssh	affected 0 before 0.52.0

CWE

No CWE identifiers supplied.

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in golang.org/x/crypto/ssh. The RSA and DSA public key parsers in the affected component did not enforce size limits on key parameters. This vulnerability allows an unauthenticated client to provide a crafted public key with an excessively large modulus or DSA parameter during public key authentication. Successful exploitation could lead to a denial of service (DoS) due to prolonged CPU consumption during signature verification.