CVE-2026-122127
CESNET ipfixcol2 2.7.1 before 2.9.0 Heap Buffer Overflow via TCP LZ4 Decoder
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.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| ipfixcol2 CESNET |
≥ 2.7.1; < 2.9.0 (affected, semver)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: VulnCheck |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/CESNET/ipfixcol2/commit/fd5cb168efb4b864d33f655174711b2779cef502CNA: VulnCheck · patch
- https://github.com/CESNET/ipfixcol2CNA: VulnCheck · product
- https://github.com/CESNET/ipfixcol2/releases/tag/v2.9.0CNA: VulnCheck · release-notes
- https://github.com/CESNET/ipfixcol2/blob/v2.8.0/src/plugins/input/tcp/src/Lz4Decoder.cpp#L139-L151CNA: VulnCheck · technical-description
- https://www.vulncheck.com/advisories/cesnet-ipfixcol2-2.7.1-before-2.9.0-heap-buffer-overflow-via-tcp-lz4-decoderCNA: VulnCheck · third-party-advisory
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