{"id":"CVE-2026-122129","published":"2026-11-04T21:18:08.380","lastModified":"2026-11-04T21:18:08.380","description":"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.","cvssScore":5.3,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwes":["CWE-789"],"vendors":[],"products":[],"references":[{"url":"https://github.com/CESNET/ipfixcol2","tags":[]},{"url":"https://github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L126-L131","tags":[]},{"url":"https://github.com/CESNET/ipfixcol2/commit/1a199033eff847941353c5c039cb806a9ad8aa6f","tags":[]},{"url":"https://github.com/CESNET/ipfixcol2/releases/tag/v2.9.0","tags":[]},{"url":"https://www.vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-memory-exhaustion-via-tcp-lz4-decoder","tags":[]}],"exploitRefs":[{"url":"https://github.com/CESNET/ipfixcol2","tags":[]},{"url":"https://github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L126-L131","tags":[]},{"url":"https://github.com/CESNET/ipfixcol2/commit/1a199033eff847941353c5c039cb806a9ad8aa6f","tags":[]},{"url":"https://github.com/CESNET/ipfixcol2/releases/tag/v2.9.0","tags":[]}],"hasPoc":true,"ai":null}