CURL-CVE-2017-8818

    Dashboard / Vulnerabilities / CURL-CVE-2017-8818

    CURL-CVE-2017-8818

    Published: 29 Nov 2017Last Modified: 27 May 2026
    Aliases:

    Summary: SSL out of buffer access

    Details: libcurl contains an out boundary access flaw in SSL related code. When allocating memory for a connection (the internal struct called `connectdata`), a certain amount of memory is allocated at the end of the struct to be used for SSL related structs. Those structs are used by the particular SSL library libcurl is built to use. The application can also tell libcurl which specific SSL library to use if it was built to support more than one. The math used to calculate the extra memory amount necessary for the SSL library was wrong on 32-bit systems, which made the allocated memory too small by 4 bytes. The last struct member of the last object within the memory area could then be outside of what was allocated. Accessing that member could lead to a crash or other undefined behaviors depending on what memory that is present there and how the particular SSL library decides to act on that memory content. Specifically the vulnerability is present if libcurl was built so that `sizeof(long long *) < sizeof(long long)` which as far as we are aware only happens in 32-bit builds.

    References:

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 7.56.0
    Fixed -7.57.0

    Affected versions

    7.56.1
    7.56.0

    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