Vulnerability in Curl
CVE-2026-6276
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (26.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Product)
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Patch, Vendor Advisory)
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Exploit, Third Party Advisory, Issue Tracking)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-6276?
- CVE-2026-6276 is a high-severity vulnerability in Curl, classified under Origin Validation Error. CVSS score: 7.5/10. Published 2026-05-13.
- How severe is CVE-2026-6276?
- High severity. CVSS v3 base score is 7.5 out of 10.