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 because of Observable Differences in Behavior to Error Inputs.
Does this matter?
Lower severity and a low EPSS score (0.92%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- EPSS
- 0.92% probability · 60th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-203
- Affected
- bouncycastle/fips java api · bouncycastle/legion-of-the-bouncy-castle
- Source
- cve@mitre.org
EPSS 0.9% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/bcgit/bc-java/wiki/CVE-2020-26939Patch, Third Party Advisory
- https://lists.apache.org/thread.html/r8c36ba34e80e05eecb1f80071cc834d705616f315b634ec0c7d8f42e%40%3Cissues.solr.apache.org%3E
- https://github.com/bcgit/bc-java/wiki/CVE-2020-26939Patch, Third Party Advisory
- https://lists.apache.org/thread.html/r8c36ba34e80e05eecb1f80071cc834d705616f315b634ec0c7d8f42e%40%3Cissues.solr.apache.org%3E
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.