Vulnerability · Published Mar 11, 2026 · Assigned by curl
CVE-2026-3784wrong proxy connection reuse with credentials
Medium 6.5
In plain English
A medium-severity security flaw in curl from curl. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.4%top 60.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.21 | curl | 8.14.1-r3 | ALPINE-CVE-2026-3784 |
| Alpine:v3.22 | curl | 8.14.1-r4 | ALPINE-CVE-2026-3784 |
| Alpine:v3.23 | curl | 8.19.0-r0 | ALPINE-CVE-2026-3784 |
| Alpine:v3.24 | curl | 8.19.0-r0 | ALPINE-CVE-2026-3784 |
| Debian:12 | curl | 7.88.1-10+deb12u15 | DEBIAN-CVE-2026-3784 |
| Debian:13 | curl | 8.14.1-2+deb13u4 | DEBIAN-CVE-2026-3784 |
| Debian:14 | curl | 8.19.0-1 | DEBIAN-CVE-2026-3784 |
| Ubuntu:22.04:LTS | curl | 7.81.0-1ubuntu1.23 | USN-8084-1 |
| Ubuntu:22.04:LTS | curl | 7.81.0-1ubuntu1.23 | UBUNTU-CVE-2026-3784 |
| Ubuntu:24.04:LTS | curl | 8.5.0-2ubuntu10.8 | USN-8084-1 |
| Ubuntu:24.04:LTS | curl | 8.5.0-2ubuntu10.8 | UBUNTU-CVE-2026-3784 |
| Ubuntu:25.10 | curl | 8.14.1-2ubuntu1.2 | UBUNTU-CVE-2026-3784 |
| Ubuntu:25.10 | curl | 8.14.1-2ubuntu1.2 | USN-8084-1 |
| Ubuntu:26.04:LTS | curl | 8.18.0-1ubuntu2 | UBUNTU-CVE-2026-3784 |
| Ubuntu:26.10 | curl | 8.18.0-1ubuntu2 | UBUNTU-CVE-2026-3784 |
Affected products (as reported)
Weakness: CWE-305 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N