CVE-2026-122129
CESNET ipfixcol2 2.7.1 before 2.9.0 Memory Exhaustion via TCP LZ4 Decoder
CVSS Score
5.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-789 |
| Vendor | cesnet |
| Product | ipfixcol2 |
| Published | Nov 4, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
CESNET / ipfixcol2
2.7.1 < 2.9.0
References
github.com: https://github.com/CESNET/ipfixcol2/commit/1a199033eff847941353c5c039cb806a9ad8aa6f github.com: https://github.com/CESNET/ipfixcol2 github.com: https://github.com/CESNET/ipfixcol2/releases/tag/v2.9.0 github.com: https://github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L126-L131 vulncheck.com: https://www.vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-memory-exhaustion-via-tcp-lz4-decoder
Credits
Deus Rex Michal Sedlak