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TI-2026-85170 Aliases CVE-2026-122129GHSA-v896-hxw5-4767

Memory exhaustion in CESNET ipfixcol2 via TCP LZ4 decoder

Priority LOW 37CWE-789Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-789.

Summary

CESNET ipfixcol2 from 2.7.1 before 2.9.0 has a memory allocation flaw in Lz4Decoder::read_start_header() that accepts unbounded ring buffer sizes (CWE-789). An unauthenticated remote attacker can open TCP connections that send LZ4 start headers with very large buffer sizes, forcing allocations of up to 4 GiB per connection and denying collector service.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00401 34th percentileScored 2026-11-07
Fix Fixed ipfixcol2 (CESNET): 2.9.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CESNETipfixcol22.7.1 to before 2.9.02.9.0Patch availableCNA
  • ipfixcol2 VendorCESNET Affected 2.7.1 to before 2.9.0 Fixed in 2.9.0 Patch available CNA

Remediation

Upgrade CESNET ipfixcol2 to version 2.9.0.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

  • Fix · CNA ipfixcol2 (CESNET) Fixed in 2.9.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    CESNET ipfixcol2 2.9.0

    3 records Highest priority Priority MEDIUM 2 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-85169 Heap buffer overflow in CESNET ipfixcol2 TCP LZ4 decoderPriority MEDIUM 44
    • TI-2026-85171 Integer overflow in CESNET ipfixcol2 Forwarder plugin enables heap overflowPriority MEDIUM 42
    Show all 3 records →

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-122129
  2. 2026-11-04 Alias added: GHSA-v896-hxw5-4767
  3. 2026-11-05 CISA SSVC decision points changed
  4. 2026-11-05 Priority changed: MEDIUM → LOW

References

Patch 1

Other 3

  • TI-2026-32573 libyang: lyb_read_string() integer overflow → heap buffer overflow CVSS 3.1HIGH 7.5
  • TI-2023-11820 libyang from v2.0.164 to v2.1.30 was discovered to contain a NULL pointer dereference via… CVSS 3.1HIGH 7.5
  • TI-2026-79264 Uninitialized pointer free in libyang NETCONF RPC parser CVSS 4.0MEDIUM 6.0
  • TI-2019-13946 Stack-based buffer overflow in Red Hat libyang CVSS 3.1CRITICAL 9.8
  • TI-2019-13945 Stack-based buffer overflow in Red Hat libyang CVSS 3.1CRITICAL 9.8
  • TI-2019-11637 The proxystatistics module before 3.1.0 for SimpleSAMLphp allows SQL Injection in lib/Auth/Process/DatabaseCommand.php. CVSS 3.0CRITICAL 9.8
See all 25 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences