RustCrypto/RSA is a portable RSA implementation in pure Rust. Due to a non-constant-time implementation, information about the private key is leaked through timing information which is observable over the network. An attacker may be able to use that information to recover the key. There is currently no fix available. As a workaround, avoid using the RSA crate in settings where attackers are able to observe timing information, e.g. local use on a non-compromised computer.

Affected: crates.io: rsa

### Impact Due to a non-constant-time implementation, information about the private key is leaked through timing information which is observable over the network. An attacker may be able to use that information to recover the key.

### Patches No patch is yet available, however work is underway to migrate to a fully constant-time implementation.

### Workarounds The only currently available workaround is to avoid using the `rsa` crate in settings where attackers are able to observe timing information, e.g. local use on a non-compromised computer is fine.

### References This vulnerability was discovered as part of the "Marvin Attack", which revealed several implementations of RSA including OpenSSL had not properly mitigated timing sidechannel attacks.

- https://rustsec.org/advisories/RUSTSEC-2023-0071.html - https://people.redhat.com/~hkario/marvin/ - https://github.com/RustCrypto/RSA/issues/19

cargo-audit-advisory-db-20231219-1.1 on GA media

Affected: crates.io: rsa

### Impact Due to a non-constant-time implementation, information about the private key is leaked through timing information which is observable over the network. An attacker may be able to use that information to recover the key.

### Patches No patch is yet available. The crypto-bigint migration ([RustCrypto/RSA#394](https://github.com/RustCrypto/RSA/pull/394)) did not close this. Tracking is [RustCrypto/RSA#626](https://github.com/RustCrypto/RSA/issues/626) (padding still not constant-time). Implicit rejection work is in [RustCrypto/RSA#680](https://github.com/RustCrypto/RSA/pull/680); default-path blinding is in [RustCrypto/RSA#702](https://github.com/RustCrypto/RSA/pull/702).

Still affected as of 2026-09-12: rsa 0.9.10 (latest stable) and rsa 0.10.0-rc.18 (latest). `patched = []` is intentional.

### Workarounds Avoid using the `rsa` crate in settings where attackers can observe timing, for example over the network. Local use on a non-compromised computer is fine.

### References This vulnerability was discovered as part of the "[Marvin Attack]", which revealed several implementations of RSA including OpenSSL had not properly mitigated timing sidechannel attacks.

[Marvin Attack]: https://people.redhat.com/~hkario/marvin/

Affected: Ubuntu:24.04:LTS: rust-rsa, Ubuntu:25.10: rust-rsa, Ubuntu:26.04:LTS: rust-rsa

RustCrypto/RSA is a portable RSA implementation in pure Rust. Due to a non-constant-time implementation, information about the private key is leaked through timing information which is observable over the network. An attacker may be able to use that information to recover the key. There is currently no fix available. As a workaround, avoid using the RSA crate in settings where attackers are able to observe timing information, e.g. local use on a non-compromised computer.