CVE-2026-122127

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    CVE-2026-122127

    Published: 4 Nov 2026Last Modified: 7 Nov 2026

    Summary: CESNET ipfixcol2 2.7.1 before 2.9.0 Heap Buffer Overflow via TCP LZ4 Decoder

    Details: CESNET ipfixcol2 2.7.1 before 2.9.0 contains a heap-based buffer overflow in Lz4Decoder.cpp that allows unauthenticated network peers to write past heap buffers. Attackers can declare a small ring buffer_size followed by a large decompressed_size to write up to 65535 controlled bytes and crash the collector.

    References: https://github.com/CESNET/ipfixcol2/releases/tag/v2.9.0, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/122xxx/CVE-2026-122127.json, https://nvd.nist.gov/vuln/detail/CVE-2026-122127, https://www.vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-heap-buffer-overflow-via-tcp-lz4-decoder, https://github.com/CESNET/ipfixcol2/commit/fd5cb168efb4b864d33f655174711b2779cef502, https://github.com/CESNET/ipfixcol2, https://github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L139-L151

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 63806311ae72da97468e9a0aaf4b1671c1f12e21
    Fixed -c731deb5486f8b8aaa1ff476d833bf8418130118

    Affected versions

    v2.8.0

    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
    CVE-2026-122127 | CVE-DB