connection reuse ignores TLS requirement
A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.
02 / AFFECTED SOFTWARE
Affected packages
139 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.
05 / REFERENCES
Further evidence
- http://www.openwall.com/lists/oss-security/2026/04/29/7
- https://curl.se/docs/CVE-2026-4873.html
- https://curl.se/docs/CVE-2026-4873.json
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4873.json
- https://hackerone.com/reports/3621851
- https://nvd.nist.gov/vuln/detail/CVE-2026-4873