6.9 Medium

CVE-2026-122129 CESNET ipfixcol2 2.7.1 before 2.9.0 Memory Exhaustion via TCP LZ4 Decoder

Description

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.

CVSS 4.0 detail

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Exploitable remotely over the network, without an account and without any user action; the impact on data or service is limited.

Attack vector: Network
Attack complexity: Low
Attack requirements: None
Privileges required: None
Interaction: None
Confidentiality: None
Integrity: None
Availability: Low
Confidentiality of other systems: None
Integrity of other systems: None
Availability of other systems: None

Affected products and versions

Product	Affected versions	Fixed in
ipfixcol2 2.7	2.7.1 → < 2.9.0	2.9.0

References

Patch Commit github.com
github.com github.com
ipfixcol2 v2.9.0 Release Notes github.com
github.com github.com
VulnCheck Advisory: CESNET ipfixcol2 2.7.1 before 2.9.0 Memory Exhaustion via TCP LZ4 Decoder www.vulncheck.com

Timeline

Published November 4, 2026
Last modified November 5, 2026

The 3 CVEs of ipfixcol2 →

CVE-2026-122130 CESNET ipfixcol2 2.3.0 before 2.9.0 Buffer Overflow via Forwarder Output Plugin 8.3 High CVE-2026-122127 CESNET ipfixcol2 2.7.1 before 2.9.0 Heap Buffer Overflow via TCP LZ4 Decoder 8.7 High

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