CESNET ipfixcol2 up to 2.8.x Lz4 Decoder Lz4Decoder.cpp buffer_size/decompressed_size buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.8$0-$5k0.69+

Summaryinfo

A vulnerability classified as critical was found in CESNET ipfixcol2 up to 2.8.x. This vulnerability affects unknown code of the file Lz4Decoder.cpp of the component Lz4 Decoder. The manipulation of the argument buffer_size/decompressed_size results in buffer overflow. This vulnerability is cataloged as CVE-2026-122127. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in CESNET ipfixcol2 up to 2.8.x. It has been classified as critical. Affected is an unknown function of the file Lz4Decoder.cpp of the component Lz4 Decoder. The manipulation of the argument buffer_size/decompressed_size with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-122127 since 11/04/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit.

Upgrading to version 2.9.0 eliminates this vulnerability.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 6.8

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: ipfixcol2 2.9.0

Timelineinfo

11/04/2026 Advisory disclosed
11/04/2026 +0 days CVE reserved
11/04/2026 +0 days VulDB entry created
11/04/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CNA: VulnCheck
CVE: CVE-2026-122127 (🔒)

GCVE (CVE): GCVE-0-2026-122127
GCVE (VulDB): GCVE-100-431214

Entryinfo

Created: 11/04/2026 22:01
Changes: 11/04/2026 22:01 (78)
Complete: 🔍
Cache ID: 216::103

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