CVE-2026-9546
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Summary
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 referrer string was erroneously
reused and sent in subsequent requests, potentially leaking sensitive
information to unintended servers.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| curl | curl | 8.18.0 < 8.20.1 | affected |
| curl | curl | 2cb868242dc2ac9cd52ee64987ef51d5964a56f9 < 862e8a74a84478d82973471b4f49dc2746c1780e | affected |
| curl | curl | 8.20.0 | affected |
| curl | curl | 8.19.0 | affected |
| curl | curl | 8.18.0 | affected |
Weaknesses
- CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: poc
- Automatable: yes
- Technical Impact: partial
Additional References
References
- https://curl.se/docs/CVE-2026-9546.json
- https://curl.se/docs/CVE-2026-9546.html
- https://hackerone.com/reports/3754343
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