CVE-2019-6486: Denial of Service in crypto/elliptic P-521 and P-384 curves
Summary
CVE-2019-6486: Denial of service affecting P-521 and P-384 curves in crypto/elliptic. Affects stdlib across 2 version ranges.
< 1.10.8
>= 1.11.0-0, < 1.11.5
Fixed in 1.10.8 or 1.11.5, depending on the release line you run. How to fix ↓
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Background
The stdlib package in the Go ecosystem provides a collection of standard libraries for the Go programming language. One of the packages included is crypto/elliptic, which implements elliptic curve cryptography. This package offers support for various elliptic curves, including P-521 and P-384. Elliptic curve cryptography is widely used for secure communication protocols, digital signatures, and key exchange mechanisms.
Vulnerability Detail
A Denial of Service (DoS) vulnerability has been identified in the crypto/elliptic implementation of the P-521 and P-384 elliptic curves. This vulnerability allows an attacker to create inputs that consume excessive amounts of CPU resources. The attacker can exploit this vulnerability through various means, such as delivering the malicious inputs via TLS handshakes, X.509 certificates, JWT tokens, ECDH shares, or ECDSA signatures. If an ECDH private key is reused multiple times, the attack can also lead to key recovery. This vulnerability poses a significant risk to systems relying on the affected elliptic curves for cryptographic operations.
How To Fix
Latest published version: go1.25.5 as of 22 Oct 2026
go get stdlib@vgo1.25.5Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 1.10.81.10.8go get stdlib@v1.10.8 -
>= 1.11.0-0, < 1.11.51.11.5go get stdlib@v1.11.5
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Workaround
There is no known workaround for this vulnerability. It is crucial to apply the recommended fix by updating the Go stdlib package to the patched versions.
Conclusion
The Denial of Service vulnerability in the P-521 and P-384 elliptic curves of the crypto/elliptic implementation in the Go stdlib package poses a significant risk to systems relying on these curves for cryptographic operations. It is crucial to update the Go stdlib package to the patched versions to mitigate this vulnerability. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for stdlib →
FAQ
This vulnerability allows an attacker to launch a DoS attack, causing excessive CPU consumption. In some cases, it can also lead to key recovery if an ECDH private key is reused.
The vulnerability can be exploited by crafting malicious inputs and delivering them through various channels, such as TLS handshakes, X.509 certificates, JWT tokens, ECDH shares, or ECDSA signatures.
Versions prior to 1.10.8 and 1.11.5 of the Go stdlib package are affected by this vulnerability.
No, there are no known workarounds for this vulnerability. Updating to the patched versions of the Go stdlib package is the recommended solution.
Key recovery is only possible if an ECDH private key is reused multiple times. It is important to avoid reusing ECDH private keys to mitigate this risk.
References
Related vulnerabilities
Recent vulnerabilities recorded for stdlib.
