High severity · published Jul 3, 2026
CVE-2026-8286
wrong STARTTLS connection reuse
8.1
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CU
curl · curl
7.30.0 before 8.14.2; 8.15.0 before 8.16.1; 8.17.0 before 8.20.1; a1701eea289fe7ea80651f801cf992838a491dde before a86efdd7ca5433de9231e650f18247de8319ad16; 8.20.0; 8.19.0; +34 more · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8286
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-8286
Patch
https://curl.se/docs/CVE-2026-8286.html
Vendor Advisory
https://curl.se/docs/CVE-2026-8286.json
Exploit
https://hackerone.com/reports/3718195
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