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GHSA-9c48-w39g-hm26 rsa

Fix: RustCrypto/RSA@2926c91

GHSA-9c48-w39g-hm26 is a CWE-703 vulnerability in rsa. A fix is available for rsa — see the affected versions and patch details below.

rsa crate has potential panic on a prime being equal to 1

Also known asCVE-2026-21895
Published
Jan 6, 2026
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • 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-9c48-w39g-hm26.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs38th percentile — riskier than 38% 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.

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

When creating a RSA private key from its components, the construction panics, instead of returning an error, when one of the primes is 1.

Discovered by Christian Reitter from Radically Open Security during a security review for Proton AG.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iorsaall versions0.9.10cargo update -p rsa --precise 0.9.10

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. Fix

    Update rsa to 0.9.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9c48-w39g-hm26 is resolved across your whole dependency graph.

  3. Workarounds

    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-9c48-w39g-hm26 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-9c48-w39g-hm26. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

When creating a RSA private key from its components, the construction panics, instead of returning an error, when one of the primes is `1`. Discovered by Christian Reitter from [Radically Open Security](https://www.radicallyopensecurity.com/) during a security review for [Proton AG](https://proton.me/).
O3 Security · Impact-Aware SCA

Is GHSA-9c48-w39g-hm26 in your dependencies?

O3 Security finds GHSA-9c48-w39g-hm26 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-9c48-w39g-hm26: rsa | O3 Security