CVE-2026-122129: CESNET ipfixcol2

CESNET ipfixcol2 2.7.1 before 2.9.0 Memory Exhaustion via TCP LZ4 Decoder

CVSS 6.9 MediumEPSS 0.0040 · 34th percentile

Published by the CVE Program (CNA: VulnCheck) at 4 Nov 2026, 20:36 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
CESNET	ipfixcol2	affected 2.7.1 to before 2.9.0 semver Other versions: unaffected

Identifiers

CVE-2026-122129

CNA

VulnCheck

Weakness (CWE)

CWE-789

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.9	Medium	4.0	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	CNA (VulnCheck)Used for this record
5.3	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0040, the 34th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

4 Nov 2026, 20:36 UTC Confirmed by the CVE List
4 Nov 2026, 20:43 UTC First seen by agentprime
4 Nov 2026, 21:18 UTC Confirmed by NVD

Sources

References from the CNA

github.com/CESNET/ipfixcol2/commit/1a199033eff847941353c5c039cb806a9ad8aa6f patch
github.com/CESNET/ipfixcol2 product
github.com/CESNET/ipfixcol2/releases/tag/v2.9.0 release-notes
github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L126-L131 technical-description
www.vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-memory-exhaustion-via-tcp-lz4-decoder third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.