CVE-2020-12607 Improper Verification of Cryptographic Signature in fastecdsa
An attacker can cause valid ECDSA signatures to fail verification for specific keys, potentially enabling denial-of-service or bypassing authentication checks in dependent systems.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-12607?
CVE-2020-12607 is a high-severity vulnerability in n/a, published on 2 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue was discovered in fastecdsa before 2.1.2. When using the NIST P-256 curve in the ECDSA implementation, the point at infinity is mishandled. This means that for an extreme value in k and s^-1, the signature verification fails even if the signature is correct. This behavior is not solely a usability problem. There are some threat models where an attacker can benefit by successfully guessing users for whom signature verification will fail.
Weakness: CWE-347
Which versions are affected by CVE-2020-12607?
3 open source packages ship an affected version, including fastecdsa. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
fastecdsa PyPI | All versions | 2.1.2 |
fastecdsa PyPI | All versions | 2.1.2 |
fastecdsa PyPI | All versions | 2.1.2 |
Products include Antonkueltz Fastecdsa.
How do I fix CVE-2020-12607?
Upgrade fastecdsa to 2.1.2 or later.
Is CVE-2020-12607 being exploited?
There is no known exploitation of CVE-2020-12607 in the wild and no public exploit code.
Other vulnerabilities in n/a
Sources
Also known as GHSA-56wv-2wr9-3h9r, PYSEC-2020-42.