CVE-2026-39829: Invoking pathological RSA/DSA parameters may cause DoS in golang.org/x/crypto/ssh
Invoking pathological RSA/DSA parameters may cause DoS in golang.org/x/crypto/ssh
Other sources
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.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
go/golang.org/x/crypto/sshto a version that resolves this vulnerability.Fixed in 0.52.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-39829?
The severity of CVE-2026-39829 is rated as 37.
How do I fix CVE-2026-39829?
To fix CVE-2026-39829, ensure you are using an updated version of golang.org/x/crypto/ssh that enforces size limits on RSA and DSA parameters.
What vulnerabilities does CVE-2026-39829 introduce?
CVE-2026-39829 allows unauthenticated clients to exploit oversized public keys, leading to potential denial of service via excessive CPU consumption.
Which software is affected by CVE-2026-39829?
CVE-2026-39829 affects the golang.org/x/crypto/ssh package used for SSH key parsing.
How can CVE-2026-39829 be triggered?
CVE-2026-39829 can be triggered by using a crafted public key with an excessively large modulus or DSA parameter.