Skip to main content
VulnerabilityPublished Updated

CVE-2026-4873: curl · Cleartext Transmission

Affects curlSource GCVE Database

0
Compare

Not known to be exploited · CVSS 5.9 Medium.

Data as of 11 Nov 2026, 23:18 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CISA-ADPCVSS 3.15.9
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
curl curlAffected
  • =7.20.0
  • =8.15.0
  • =8.17.0
Fixed in–

AI-suggested

Until a fix is available, avoid reusing connection pools for protocols requiring TLS or configure curl to enforce TLS strictly for each connection. Monitor vendor communications for updates.

Description

CVE-2026-4873 is a medium severity vulnerability in curl where a connection that should use TLS incorrectly reuses an existing unencrypted connection from the same connection pool. This causes subsequent requests to the same host to bypass TLS and transmit sensitive data in cleartext, affecting protocols like IMAP, SMTP, and POP3.

References

Community reviews

Loading reviews…