CVE-2026-122129

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    CVE-2026-122129

    Published: 4 Nov 2026Last Modified: 7 Nov 2026

    Summary: CESNET ipfixcol2 2.7.1 before 2.9.0 Memory Exhaustion via TCP LZ4 Decoder

    Details: CESNET ipfixcol2 2.7.1 before 2.9.0 contains a memory allocation vulnerability in Lz4Decoder::read_start_header() that allows unauthenticated attackers to exhaust memory by declaring unbounded ring buffer sizes. Attackers can open TCP connections sending LZ4 start headers with very large buffer sizes, forcing up to 4 GiB allocations per connection and denying collector service.

    References: https://github.com/CESNET/ipfixcol2/releases/tag/v2.9.0, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/122xxx/CVE-2026-122129.json, https://nvd.nist.gov/vuln/detail/CVE-2026-122129, https://www.vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-memory-exhaustion-via-tcp-lz4-decoder, https://github.com/CESNET/ipfixcol2/commit/1a199033eff847941353c5c039cb806a9ad8aa6f, https://github.com/CESNET/ipfixcol2, https://github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L126-L131

    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-2026-122129 | CVE-DB