CVE-2026-122127

High

Description

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductCesnet Ipfixcol2

PublishedNov 4, 2026

First seenNov 4, 2026

Weakness typeCWE-787Out-of-bounds write

How to fix

Update

CESNET ipfixcol22.9.0 or later

Patches

github.com/CESNET/ipfixcol2/commit/fd5cb168efb4b864d33f655174711b2779cef502

Vendor advisories

github.com/CESNET/ipfixcol2/releases/tag/v2.9.0

Affected products

Product	Affected versions	Fixed in
CESNET ipfixcol2	2.7.1 ≤ v < 2.9.0	2.9.0

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