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MEDIUM severity

GHSA-72m5-fvvv-55m6 bcprov-jdk14

MEDIUMFix: bcgit/bc-java@930f8b2

GHSA-72m5-fvvv-55m6 is a medium-severity (CVSS 5.3) CWE-203 vulnerability in org.bouncycastle:bcprov-jdk14. A fix is available for org.bouncycastle:bcprov-jdk14 — see the affected versions and patch details below.

Observable Differences in Behavior to Error Inputs in Bouncy Castle

Also known asCVE-2020-26939
Published
Apr 22, 2021
Updated
Jul 17, 2025
Affected
8 pkgs
Patched
8 / 8
Exploits
None indexed
Exploitation data as of Sep 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs59th percentile — riskier than 59% 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-72m5-fvvv-55m6 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 377,166 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

8 pkgs affected
org.bouncycastle:bcprov-jdk14org.bouncycastle:bcprov-jdk15org.bouncycastle:bcprov-jdk16org.bouncycastle:bc-fipsorg.bouncycastle:bcprov-ext-jdk15onorg.bouncycastle:bcprov-ext-jdk16org.bouncycastle:bcprov-jdk15onorg.bouncycastle:bcprov-jdk15to18

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

Description

In Legion of the Bouncy Castle BC before 1.55 and BC-FJA before 1.0.2, attackers can obtain sensitive information about a private exponent because of Observable Differences in Behavior to Error Inputs. This occurs in org.bouncycastle.crypto.encodings.OAEPEncoding. Sending invalid ciphertext that decrypts to a short payload in the OAEP Decoder could result in the throwing of an early exception, potentially leaking some information about the private exponent of the RSA private key performing the encryption.

Affected Packages

8 total 8 fixed
EcosystemPackageVulnerable rangeFix
Mavenorg.bouncycastle:bcprov-jdk14all versions1.61org.bouncycastle:bcprov-jdk14:1.61
Mavenorg.bouncycastle:bcprov-jdk15all versions1.61org.bouncycastle:bcprov-jdk15:1.61
Mavenorg.bouncycastle:bcprov-jdk16all versions1.61org.bouncycastle:bcprov-jdk16:1.61
Mavenorg.bouncycastle:bc-fipsall versions1.0.2org.bouncycastle:bc-fips:1.0.2
Mavenorg.bouncycastle:bcprov-ext-jdk15onall versions1.61org.bouncycastle:bcprov-ext-jdk15on:1.61
Mavenorg.bouncycastle:bcprov-ext-jdk16all versions1.61org.bouncycastle:bcprov-ext-jdk16:1.61

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.bouncycastle:bcprov-jdk14, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.bouncycastle:bcprov-jdk14 to 1.61 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-72m5-fvvv-55m6 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-72m5-fvvv-55m6 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-72m5-fvvv-55m6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In Legion of the Bouncy Castle BC before 1.55 and BC-FJA before 1.0.2, attackers can obtain sensitive information about a private exponent because of Observable Differences in Behavior to Error Inputs. This occurs in org.bouncycastle.crypto.encodings.OAEPEncoding. Sending invalid ciphertext that decrypts to a short payload in the OAEP Decoder could result in the throwing of an early exception, potentially leaking some information about the private exponent of the RSA private key performing the encryption.
O3 Security · Impact-Aware SCA

Is GHSA-72m5-fvvv-55m6 in your dependencies?

O3 Security finds GHSA-72m5-fvvv-55m6 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-72m5-fvvv-55m6: Medium 5.3 severity | O3 Security