How severe is CVE-2026-40562?

CVE-2026-40562 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-2026-40562 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40562?

CVE-2026-40562 affects Kazeburo Gazelle. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40562?

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.

Does CVE-2026-40562 have an EU (EUVD) identifier?

Yes. CVE-2026-40562 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27825.

When was CVE-2026-40562 published?

CVE-2026-40562 was published on 2026-05-06 and last updated on 2026-06-17.

CVE-2026-40562

CVE-2026-40562 is a high-severity vulnerability in Kazeburo Gazelle 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)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27825
Weakness: CWE-444
Affected product: Kazeburo Gazelle
Published: 2026-05-06
Last modified: 2026-06-17

Description

Gazelle versions through 0.49 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Gazelle incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.

Frequently asked questions

What is CVE-2026-40562?: Gazelle versions through 0.49 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Gazelle incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.
How severe is CVE-2026-40562?: CVE-2026-40562 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-2026-40562 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40562?: CVE-2026-40562 affects Kazeburo Gazelle. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40562?: 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.
Does CVE-2026-40562 have an EU (EUVD) identifier?: Yes. CVE-2026-40562 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27825.
When was CVE-2026-40562 published?: CVE-2026-40562 was published on 2026-05-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:kazeburo:gazelle:*:*:*:*:*:perl:*:*

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