CVE-2026-21895 rsa crate has potential panic on a prime being equal to 1
An attacker can cause a denial of service by providing a prime value of 1 during RSA private key construction, triggering a panic.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-21895?
CVE-2026-21895 is a low-severity denial of service vulnerability in RustCrypto RSA, published on 8 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The `rsa` crate is an RSA implementation written in rust. Prior to version 0.9.10, when creating a RSA private key from its components, the construction panics instead of returning an error when one of the primes is `1`. Version 0.9.10 fixes the issue.
Weakness: CWE-703
Which versions are affected by CVE-2026-21895?
2 open source packages ship an affected version, including rsa. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
rsa crates.io | All versions | 0.9.10 |
rsa crates.io | All versions | 0.9.10 |
Linux distribution packages (1)
teleport openSUSE:Tumbleweed | All versions | 17.7.14-1.1 |
Products include Rustcrypto Rsa.
How do I fix CVE-2026-21895?
Upgrade rsa to 0.9.10 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-21895 being exploited?
There is no known exploitation of CVE-2026-21895 in the wild and no public exploit code.
Other vulnerabilities in RustCrypto RSA
Sources
Also known as DEBIAN-CVE-2026-21895, GHSA-9c48-w39g-hm26, MINI-6hrw-2hmh-mc9r, MINI-xhmg-5q96-8j6v, UBUNTU-CVE-2026-21895, openSUSE-SU-2026:10105-1.