How severe is CVE-2021-41732?

CVE-2021-41732 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-41732 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41732?

CVE-2021-41732 affects Zeek. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-41732?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-41732 published?

CVE-2021-41732 was published on 2021-09-29 and last updated on 2026-06-17.

CVE-2021-41732

CVE-2021-41732 is a high-severity vulnerability in Zeek with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-444.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-444
Affected product: Zeek
Published: 2021-09-29
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2021-41732?: 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
How severe is CVE-2021-41732?: CVE-2021-41732 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-41732 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41732?: CVE-2021-41732 affects Zeek. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41732?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-41732 published?: CVE-2021-41732 was published on 2021-09-29 and last updated on 2026-06-17.

References

https://github.com/zeek/zeek/issues/1798

Affected products (1)

cpe:2.3:a:zeek:zeek:4.1.0:*:*:*:*:*:*:*

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