CESNET ipfixcol2 up to 2.8.x Lz4 Decoder read_start_header allocation of resources

CVSS Meta Temp Score
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CTI Interest Score
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6.3$0-$5k0.00+

Summaryinfo

A vulnerability, which was classified as critical, was found in CESNET ipfixcol2 up to 2.8.x. Impacted is the function Lz4Decoder::read_start_header of the component Lz4 Decoder. Such manipulation leads to allocation of resources. This vulnerability is documented as CVE-2026-122129. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in CESNET ipfixcol2 up to 2.8.x. It has been rated as critical. Affected by this issue is the function Lz4Decoder::read_start_header of the component Lz4 Decoder. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-122129 since 11/04/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 2.9.0 eliminates this vulnerability. Applying the patch 1a199033eff847941353c5c039cb806a9ad8aa6f is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.3
CNA Vector (VulnCheck): 🔒

CVSSv2info

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

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
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
Patch: 1a199033eff847941353c5c039cb806a9ad8aa6f

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-2026-122129 (🔒)

GCVE (CVE): GCVE-0-2026-122129
GCVE (VulDB): GCVE-100-431216

Entryinfo

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

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