CVE-2023-1732 Improper random reading in CIRCL
Failure to check random number generation errors in CIRCL can lead to predictable shared secrets and weak blinding, compromising cryptographic security.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2023-1732?
CVE-2023-1732 is a medium-severity vulnerability in Cloudflare CIRCL, published on 10 May 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
When sampling randomness for a shared secret, the implementation of Kyber and FrodoKEM, did not check whether crypto/rand.Read() returns an error. In rare deployment cases (error thrown by the Read() function), this could lead to a predictable shared secret.
The tkn20 and blindrsa components did not check whether enough randomness was returned from the user provided randomness source. Typically the user provides crypto/rand.Reader, which in the vast majority of cases will always return the right number random bytes. In the cases where it does not, or the user provides a source that does not, the blinding for blindrsa is weak and integrity of the plaintext is not ensured in tkn20.
Which versions are affected by CVE-2023-1732?
3 open source packages ship an affected version, including github.com/cloudflare/circl. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cloudflare/circl Go | All versions | 1.3.3 |
github.com/cloudflare/circl Go | All versions | 1.3.3 |
github.com/cloudflare/circl Go | All versions | 1.3.3 |
Products include Cloudflare Circl.
How do I fix CVE-2023-1732?
Upgrade github.com/cloudflare/circl to 1.3.3 or later.
Is CVE-2023-1732 being exploited?
There is no known exploitation of CVE-2023-1732 in the wild and no public exploit code.
Other vulnerabilities in Cloudflare CIRCL
Sources
Also known as GHSA-2q89-485c-9j2x, GO-2023-1765.