Cyber Resilience

CVE-2026-9546

Haxx Curl 8.18.0 – 8.21.0

Public PoC
Published
03 July 2026
Modified
07 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0065 49th percentile
Risk Priority 58 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-9546 is a high-severity an unspecified weakness vulnerability in Haxx Curl. Its CVSS base score is 7.5 (High).

Operationally, ranked at the 49th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability Data

A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared. While the documentation states that passing NULL to `CURLOPT_REFERER` suppresses the header, the option failed to clear the internal state. As a result the previous…

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referrer string was erroneously reused and sent in subsequent requests, potentially leaking sensitive information to unintended servers.

CWE(s)
NVD-CWE-noinfo

Related Threats

CVEs Like This One

CVE-2026-8458Same product: Haxx Curl
CVE-2026-5773Same product: Haxx Curl
CVE-2025-15079Same product: Haxx Curl
CVE-2024-0853Same product: Haxx Curl
CVE-2026-3784Same product: Haxx Curl
CVE-2026-3805Same product: Haxx Curl
CVE-2026-10536Same product: Haxx Curl
CVE-2025-14819Same product: Haxx Curl
CVE-2026-11586Same product: Haxx Curl
CVE-2025-15224Same product: Haxx Curl

Affected Assets

haxx
curl
8.18.0 — 8.21.0

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References