Answer in brief
CVE-2026-122127 records a High severity (CVSS 8.7) vulnerability in CESNET ipfixcol2 2.7.1 before 2.9.0 Heap Buffer Overflow via TCP LZ4 Decoder. The current sources do not mark it as known exploited. The current feed maps CESNET/ipfixcol2 (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps CESNET/ipfixcol2 (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| CESNET/ipfixcol2generic | >=2.7.1 <2.9.0 | 2.9.0 |
Published upstream
Nov 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 4, 2026
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.
Quoted source text, attributed separately from HOL analysis.