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MEDIUM severity

GHSA-4grx-2x9w-596c rsa

MEDIUM

GHSA-4grx-2x9w-596c is a medium-severity (CVSS 5.9) CWE-385 vulnerability in rsa. No vendor fix is recorded yet; mitigation options are listed below.

Marvin Attack: potential key recovery through timing sidechannels

Also known asCVE-2023-49092GHSA-c38w-74pg-36hrRUSTSEC-2023-0071
Published
Nov 28, 2023
Updated
Sep 10, 2026
Affected
1 pkg
Patched
None yet
Exploits
None indexed
Exploitation data as of Sep 20, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-4grx-2x9w-596c.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs48th percentile — riskier than 48% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-4grx-2x9w-596c plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🦀rsa

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
🦀crates.iorsaall versionsNo fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rsa, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    No patched version of rsa has shipped for GHSA-4grx-2x9w-596c yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-4grx-2x9w-596c can be triaged on real exposure rather than presence alone.

Tailored to GHSA-4grx-2x9w-596c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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. [Marvin Attack]: https://people.redhat.com/~hkario/marvin/
O3 Security · Impact-Aware SCA

Is GHSA-4grx-2x9w-596c in your dependencies?

O3 Security finds GHSA-4grx-2x9w-596c across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-4grx-2x9w-596c: rsa (Medium 5.9) | O3 Security