CURL-CVE-2019-5482

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    CURL-CVE-2019-5482

    Published: 11 Sept 2019Last Modified: 27 May 2026
    Aliases:

    Summary: TFTP small blocksize heap buffer overflow

    Details: libcurl contains a heap buffer overflow in the function (`tftp_receive_packet()`) that receives data from a TFTP server. It can call `recvfrom()` with the default size for the buffer rather than with the size that was used to allocate it. Thus, the content that might overwrite the heap memory is controlled by the server. This flaw is only triggered if the TFTP server sends an `OACK` without the `BLKSIZE` option, when a `BLKSIZE` smaller than 512 bytes was requested by the TFTP client. `OACK` is a TFTP extension and is not used by all TFTP servers. Users choosing a smaller block size than default should be rare as the primary use case for changing the size is to make it larger. It is rare for users to use TFTP across the Internet. It is most commonly used within local networks. TFTP as a protocol is always inherently insecure. This issue was introduced by the add of the TFTP `BLKSIZE` option handling. It was previously incompletely fixed by an almost identical issue called CVE-2019-5436.

    References:

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 7.19.4
    Fixed -7.66.0

    Affected versions

    7.65.3
    7.65.2
    7.65.1
    7.65.0

    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