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CVE-2026-122127

7.5, high

CESNET ipfixcol2 Out-of-Bounds Write Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
7.5, high high CVSS v3.1
EPSS, next 30 days
n/a
Exploitation
No public evidence
Published
4 Nov 2026yesterday

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.

Details

Vendor
CESNET
Product
ipfixcol2
Weakness
CWE-787 (opens in a new tab)
Status
Received
Updated
4 Nov 2026
Assigner
disclosure@vulncheck.com

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References 5

Patches and fixes 1

Other references 4

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other CESNET CVEs

Every CESNET CVE we hold

Same vendor in what we hold, not a known link between the flaws.

Beyond this page

Is CVE-2026-122127 in your network?

This page tells you how dangerous CVE-2026-122127 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 5 Nov 2026, not the live upstream state.