Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Haxx | Curl | >= 7.20.0, < 8.20.0 |
Related Weaknesses (CWE)
References
- https://curl.se/docs/CVE-2026-4873.htmlPatchVendor Advisory
- https://curl.se/docs/CVE-2026-4873.jsonVendor Advisory
- https://hackerone.com/reports/3621851ExploitIssue TrackingThird Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/29/7Mailing ListPatchThird Party Advisory
FAQ
What is CVE-2026-4873?
CVE-2026-4873 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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, SMT...
How severe is CVE-2026-4873?
CVE-2026-4873 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-4873?
Check the references section above for vendor advisories and patch information. Affected products include: Haxx Curl.