CESNET ipfixcol2 2.7.1 before 2.9.0 contains a heap-based buffer overflow in Lz4Decoder.cpp that allows
Source GCVE Database
Not known to be exploited · CVSS 8.7 High : upgrade to 2.9.0 soon.
Data as of 4 Nov 2026, 22:52 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 8.7 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 7.5 |
- Patch
- Available – fixed in 2.9.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 4 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.
What to do
Upgrade ipfixcol2 and cesnet/ipfixcol2 to 2.9.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| CESNETipfixcol2 | Affected
| Fixed in
|
GitHubcesnet/ipfixcol2pkg:github/cesnet/ipfixcol2Other threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fixed version 2.9.0 or later should be applied to remediate this vulnerability. Until patched, restricting network access to trusted peers may reduce exposure.
Description
CESNET ipfixcol2 versions 2.7.1 up to but not including 2.9.0 contain a heap-based buffer overflow vulnerability in the Lz4Decoder.cpp component. This flaw allows unauthenticated network peers to write beyond heap buffer boundaries by manipulating buffer size parameters, potentially crashing the collector service. The vulnerability has a high severity score of 7.5 and impacts availability without affecting confidentiality or integrity.
References
- nvd.nist.gov/vuln/detail/CVE-2026-122127 (opens in a new tab)
- github.com/CESNET/ipfixcol2/commit/fd5cb168efb4b864d33f655174711b2779cef502 (opens in a new tab)
- github.com/CESNET/ipfixcol2 (opens in a new tab)
- github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp (opens in a new tab)
- github.com/CESNET/ipfixcol2/releases/tag/v2.9.0 (opens in a new tab)
- vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-heap-buffer-overflow-via-tcp-lz4-decoder (opens in a new tab)