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MEDIUM severity

GHSA-5jjv-x4fq-qjwp

MEDIUMFix: shrinerb/shrine@1b27090

GHSA-5jjv-x4fq-qjwp is a medium-severity (CVSS 5.9) CWE-203 vulnerability in shrine. O3 Security confirms whether GHSA-5jjv-x4fq-qjwp is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Possible timing attack in derivation_endpoint

Also known asCVE-2020-15237
Published
Oct 5, 2020
Updated
Jul 8, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Jul 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
💎shrine

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

Description

Impact

When using the derivation_endpoint plugin, it's possible for the attacker to use a timing attack to guess the signature of the derivation URL.

Patches

The problem has been fixed by comparing sent and calculated signature in constant time, using Rack::Utils.secure_compare. Users using the derivation_endpoint plugin are urged to upgrade to Shrine 3.3.0 or greater.

Workarounds

Users of older Shrine versions can apply the following monkey-patch after loading the derivation_endpoint plugin:

class Shrine
  class UrlSigner
    def verify_signature(string, signature)
      if signature.nil?
        fail InvalidSignature, "missing \"signature\" param"
      elsif !Rack::Utils.secure_compare(signature, generate_signature(string))
        fail InvalidSignature, "provided signature does not match the calculated signature"
      end
    end
  end
end

References

You can read more about timing attacks here.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsshrineall versions3.3.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for shrine. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update shrine to 3.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5jjv-x4fq-qjwp 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 pinpoints whether GHSA-5jjv-x4fq-qjwp is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-5jjv-x4fq-qjwp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact When using the `derivation_endpoint` plugin, it's possible for the attacker to use a timing attack to guess the signature of the derivation URL. ### Patches The problem has been fixed by comparing sent and calculated signature in constant time, using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine 3.3.0 or greater. ### Workarounds Users of older Shrine versions can apply the following monkey-patch after loading the `derivation_endpoint` plugin: ```rb class Shrine class UrlSigner def verify_signature(string, signat
O3 Security · Impact-Aware SCA

Is GHSA-5jjv-x4fq-qjwp in your dependencies?

O3 detects GHSA-5jjv-x4fq-qjwp across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

GHSA-5jjv-x4fq-qjwp: Possible timing attack… | O3 Security