CVE-2026-4873

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 v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://curl.se/docs/CVE-2026-4873.html	Patch Vendor Advisory
https://curl.se/docs/CVE-2026-4873.json	Vendor Advisory
https://hackerone.com/reports/3621851	Exploit Issue Tracking Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/04/29/7	Mailing List Patch Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-05-13 13:01

Updated : 2026-09-15 07:16

NVD link : CVE-2026-4873

Mitre link : CVE-2026-4873

CVE.ORG link : CVE-2026-4873

JSON object : View

Products Affected

haxx

curl

CWE

CWE-319

Cleartext Transmission of Sensitive Information

CWE-295

Improper Certificate Validation

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If an initial\ntransfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request\nto that same host bypasses the TLS requirement and instead transmit data\nunencrypted."}], "lastModified": "2026-09-15T07:16:28.367", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "50906082-180F-4E8B-A3E5-AC2C14B54B89", "versionEndExcluding": "8.20.0", "versionStartIncluding": "7.20.0"}], "operator": "OR"}]}], "sourceIdentifier": "2499f714-1537-4658-8207-48ae4bb9eae9"}