CVE-2026-4873

Summary

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.

Impact & exploitability

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products we track (1)

Recommendation

Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.

Official patch: https://curl.se/docs/CVE-2026-4873.html ↗

Additional information

• NVD record
• https://curl.se/docs/CVE-2026-4873.htmlPatch
• http://www.openwall.com/lists/oss-security/2026/04/29/7Patch
• https://curl.se/docs/CVE-2026-4873.jsonAdvisory
• https://hackerone.com/reports/3621851Advisory