Vulnerability MediumRUSTSEC-2023-0071 · rsa
RUSTSEC-2023-0071: Marvin Attack: potential key recovery through timing sidechannels
Short answerA security vulnerability in the rsa crate: Marvin Attack: potential key recovery through timing sidechannels. Medium severity (CVSS 5.9). No fixed version: replace the crate or remove the affected code path.
| Crate | rsa |
|---|---|
| Type | Vulnerability (crypto-failure) |
| Affected versions | Every version. |
| Fixed in | none |
| Severity | Medium, CVSS 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| Published | 2023-11-22 |
| Last changed | 2026-09-14 |
| Also known as | CVE-2023-49092, GHSA-4grx-2x9w-596c, GHSA-c38w-74pg-36hr |
What to do
- Find who pulls it in:
cargo tree -i rsa. - Avoid the affected API, or replace the crate.
Details from the advisory
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.
References
- Package: crates.io/crates/rsa
- Advisory: rustsec.org/advisories/RUSTSEC-2023-0071.html
- Report: github.com/RustCrypto/RSA/issues/626
- Report: github.com/RustCrypto/RSA/issues/19#issuecomment-1822995643
- Web: people.redhat.com/~hkario/marvin/
- Web: github.com/RustCrypto/RSA/pull/394
- Web: github.com/RustCrypto/RSA/pull/680
- Web: github.com/RustCrypto/RSA/pull/702
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for rsa
Up next
Same cratersa: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?