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    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. 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.

    Published:Nov 2, 2020
    Last Modified:Jul 17, 2025
    EPS:Nov 2, 2020
    EPSS Score:0.02027
    CVSS Score:5.3

    Affected Products

    Vendor
    Bouncycastle
    Product
    Fips Java Api
    Vendor
    Bouncycastle
    Product
    Legion-of-the-bouncy-castle

    Exploits

    No exploit reference

    Common Weakness Enumeration

    CWE-203 Observable Discrepancy

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-189 Black Box Reverse Engineering

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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High