CVE-2026-6276
stale custom cookie host causes cookie leak
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
1th
Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.
| Vendor | curl |
| Product | curl |
| Published | May 13, 2026 |
| Last Updated | May 13, 2026 |
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Affected Versions
curl / curl
8.19.0 ≤ 8.19.0 8.18.0 ≤ 8.18.0 8.17.0 ≤ 8.17.0 8.16.0 ≤ 8.16.0 8.15.0 ≤ 8.15.0 8.14.1 ≤ 8.14.1 8.14.0 ≤ 8.14.0 8.13.0 ≤ 8.13.0 8.12.1 ≤ 8.12.1 8.12.0 ≤ 8.12.0 8.11.1 ≤ 8.11.1 8.11.0 ≤ 8.11.0 8.10.1 ≤ 8.10.1 8.10.0 ≤ 8.10.0 8.9.1 ≤ 8.9.1 8.9.0 ≤ 8.9.0 8.8.0 ≤ 8.8.0 8.7.1 ≤ 8.7.1 8.7.0 ≤ 8.7.0 8.6.0 ≤ 8.6.0 8.5.0 ≤ 8.5.0 8.4.0 ≤ 8.4.0 8.3.0 ≤ 8.3.0 8.2.1 ≤ 8.2.1 8.2.0 ≤ 8.2.0 8.1.2 ≤ 8.1.2 8.1.1 ≤ 8.1.1 8.1.0 ≤ 8.1.0 8.0.1 ≤ 8.0.1 8.0.0 ≤ 8.0.0 7.88.1 ≤ 7.88.1 7.88.0 ≤ 7.88.0 7.87.0 ≤ 7.87.0 7.86.0 ≤ 7.86.0 7.85.0 ≤ 7.85.0 7.84.0 ≤ 7.84.0 7.83.1 ≤ 7.83.1 7.83.0 ≤ 7.83.0 7.82.0 ≤ 7.82.0 7.81.0 ≤ 7.81.0 7.80.0 ≤ 7.80.0 7.79.1 ≤ 7.79.1 7.79.0 ≤ 7.79.0 7.78.0 ≤ 7.78.0 7.77.0 ≤ 7.77.0 7.76.1 ≤ 7.76.1 7.76.0 ≤ 7.76.0 7.75.0 ≤ 7.75.0 7.74.0 ≤ 7.74.0 7.73.0 ≤ 7.73.0 7.72.0 ≤ 7.72.0 7.71.1 ≤ 7.71.1 7.71.0 ≤ 7.71.0
References
Credits
Muhamad Arga Reksapati Daniel Stenberg