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TI-2021-18391 Aliases CVE-2021-41732GHSA-82p3-37jm-2r8w

An issue was discovered in zeek version 4.1.0.

Priority HIGH 75CWE-444Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · High · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.

Summary

An issue was discovered in zeek version 4.1.0. There is a HTTP request splitting vulnerability that will invalidate any ZEEK HTTP based security analysis. NOTE: the vendor's position is that the observed behavior is intended

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00878 59th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:zeek:zeek:4.1.0:*:*:*:*:*:*:*4.1.0Vulnerablezeek
  • cpe:2.3:a:zeek:zeek:4.1.0:*:*:*:*:*:*:* Versions 4.1.0 Vulnerable ·zeek

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-41732
  2. 2026-10-03 Alias added: GHSA-82p3-37jm-2r8w

References

Exploit 1

  • TI-2026-42831 Zeek < 8.0.9 Null Pointer Dereference DoS via Kerberos KRB_ERROR Parsing CVSS 4.0HIGH 8.7
  • TI-2026-42830 Zeek < 8.0.9 Uncontrolled Memory Consumption DoS via FTP Analyzer CVSS 4.0HIGH 8.7
  • TI-2019-09093 In Zeek Network Security Monitor (formerly known as Bro) before 2.6.2, a NULL pointer… CVSS 3.0HIGH 7.5

Sources

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