JLSEC-2026-438 Medium 6.5

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the...

JLSEC Published: May 4, 2026
Modified: Jul 17, 2026
Severity: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected Packages: CURL_jll < 8.20.0+0
LibCURL_jll < 8.18.0+0
Upstream: CVE-2026-3784 GHSA-5q3w-6p3j-mw6p EUVD-2026-11139

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection.

References

http://www.openwall.com/lists/oss-security/2026/03/11/3
https://cert-portal.siemens.com/productcert/html/ssa-253495.html
https://curl.se/docs/CVE-2026-3784.html
https://curl.se/docs/CVE-2026-3784.json
https://github.com/advisories/GHSA-5q3w-6p3j-mw6p
https://hackerone.com/reports/3584903
https://nvd.nist.gov/vuln/detail/CVE-2026-3784