UBUNTU-CVE-2021-40530

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    UBUNTU-CVE-2021-40530

    Published: 6 Sept 2021Last Modified: 20 May 2026
    Upstream:
    CVE-2021-40530

    Summary:

    Details: The ElGamal implementation in Crypto++ through 8.5 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.

    References: https://ubuntu.com/security/CVE-2021-40530, https://eprint.iacr.org/2021/923, https://github.com/weidai11/cryptopp/issues/1059, https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1, https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2, https://www.cve.org/CVERecord?id=CVE-2021-40530

    Affected packages

    Package

    Name: libcrypto++

    Purl: pkg:deb/ubuntu/libcrypto%2B%2B?arch=source&distro=esm-infra-legacy%2Ftrusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    5.6.1-6
    5.6.1-6+deb8u1build0.14.04.1
    5.6.1-6+deb8u3build0.14.04.1
    5.6.1-6+deb8u3ubuntu0.1~esm1

    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
    UBUNTU-CVE-2021-40530 | CVE-DB