CVE-2026-4873

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-13 13:01 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-15 07:16 UTC Last updatedMost recent change to the record

Details

Published

2026-05-13 13:01 UTC

Last modified

2026-09-15 07:16 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-319 · Cleartext transmission

Record status

Modified

Affected

• Haxx Curl < 8.20.0

Attack profile CVSS 3.1 · 5.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None