CVE-2023-49092

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.

The Marvin Attack is a timing sidechannel vulnerability which allows performing RSA decryption and signing operations as an attacker with the ability to observe only the time of the decryption operation performed withthe private key.

A recent survey of RSA implementations found that the Rust rsa crate is one of many implementations vulnerable to this attack.

No fixed version is available at this time.

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

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) did not close this. Tracking is RustCrypto/RSA#626 (padding still not constant-time). Implicit rejection work is in RustCrypto/RSA#680; default-path blinding is in RustCrypto/RSA#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.

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.

These are all security issues fixed in the cargo-audit-advisory-db-20231219-1.1 package on the GA media of openSUSE Tumbleweed.