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.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Curl
  • Curl

No data.

No data.

References
Link Providers
https://www.spirityenterprise.com/virtual-ciso spirity
https://curl.se/docs/CVE-2026-4873.html cve-icon cve-icon
https://curl.se/docs/CVE-2026-4873.json cve-icon
https://hackerone.com/reports/3621851 cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-4873 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-4873 cve-icon
History

Wed, 13 May 2026 09:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in curl. A remote attacker could exploit this by initiating an unencrypted connection (via IMAP, SMTP, or POP3) and then making a subsequent request to the same host that requires Transport Layer Security (TLS). Due to incorrect connection reuse, the subsequent request would bypass the TLS requirement, leading to the transmission of sensitive information in cleartext. This vulnerability, categorized as Cleartext Transmission of Sensitive Information (CWE-319), results in information disclosure. 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.
Title curl: curl: Information disclosure due to incorrect TLS connection reuse connection reuse ignores TLS requirement
References

Fri, 01 May 2026 01:45:00 +0000

Type Values Removed Values Added
First Time appeared Curl
Curl curl
Vendors & Products Curl
Curl curl

Fri, 01 May 2026 00:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in curl. A remote attacker could exploit this by initiating an unencrypted connection (via IMAP, SMTP, or POP3) and then making a subsequent request to the same host that requires Transport Layer Security (TLS). Due to incorrect connection reuse, the subsequent request would bypass the TLS requirement, leading to the transmission of sensitive information in cleartext. This vulnerability, categorized as Cleartext Transmission of Sensitive Information (CWE-319), results in information disclosure.
Title curl: curl: Information disclosure due to incorrect TLS connection reuse
Weaknesses CWE-319
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N'}

threat_severity

Moderate
cve-icon MITRE

Status: PUBLISHED

Assigner: curl

Published:

Updated: 2026-05-13T09:05:12.559Z

Reserved: 2026-03-26T05:38:02.098Z

Link: CVE-2026-4873

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-29T00:00:00Z

Links: CVE-2026-4873 - Bugzilla