Vulnerability · Published Jul 3, 2026 · Assigned by curl
CVE-2026-8286wrong STARTTLS connection reuse
High 8.1
In plain English
A high-severity improper certificate validation in curl from curl. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.3%top 76.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | curl | 7.61.1-34.el8_10.13 | ALSA-2026:57462 |
| AlmaLinux:9 | curl | 7.76.1-40.el9_8.5 | ALSA-2026:55439 |
| AlmaLinux:9 | curl-minimal | 7.76.1-40.el9_8.5 | ALSA-2026:55439 |
| AlmaLinux:8 | libcurl | 7.61.1-34.el8_10.13 | ALSA-2026:57462 |
| AlmaLinux:9 | libcurl | 7.76.1-40.el9_8.5 | ALSA-2026:55439 |
| AlmaLinux:8 | libcurl-devel | 7.61.1-34.el8_10.13 | ALSA-2026:57462 |
| AlmaLinux:9 | libcurl-devel | 7.76.1-40.el9_8.5 | ALSA-2026:55439 |
| AlmaLinux:8 | libcurl-minimal | 7.61.1-34.el8_10.13 | ALSA-2026:57462 |
| AlmaLinux:9 | libcurl-minimal | 7.76.1-40.el9_8.5 | ALSA-2026:55439 |
| Alpine:v3.21 | curl | 8.14.1-r3 | ALPINE-CVE-2026-8286 |
| Alpine:v3.22 | curl | 8.14.1-r4 | ALPINE-CVE-2026-8286 |
| Alpine:v3.23 | curl | 8.22.0-r0 | ALPINE-CVE-2026-8286 |
| Alpine:v3.24 | curl | 8.21.0-r0 | ALPINE-CVE-2026-8286 |
| Debian:12 | curl | no fix listed | DEBIAN-CVE-2026-8286 |
| Debian:13 | curl | 8.14.1-2+deb13u7 | DEBIAN-CVE-2026-8286 |
| Debian:14 | curl | 8.21.0~rc2-1 | DEBIAN-CVE-2026-8286 |
| Rocky Linux:8 | curl | 0:7.61.1-34.el8_10.13 | RLSA-2026:57462 |
| Rocky Linux:9 | curl | 0:7.76.1-40.el9_8.5 | RLSA-2026:55439 |
| Ubuntu:22.04:LTS | curl | 7.81.0-1ubuntu1.25 | UBUNTU-CVE-2026-8286 |
| Ubuntu:24.04:LTS | curl | 8.5.0-2ubuntu10.10 | UBUNTU-CVE-2026-8286 |
| Ubuntu:25.10 | curl | 8.14.1-2ubuntu1.4 | UBUNTU-CVE-2026-8286 |
| Ubuntu:26.04:LTS | curl | 8.18.0-1ubuntu2.2 | UBUNTU-CVE-2026-8286 |
Affected products (as reported)
Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N