Description
A use after free vulnerability exists in curl <7.87.0. Curl can be asked to *tunnel* virtually all protocols it supports through an HTTP proxy. HTTP proxies can (and often do) deny such tunnel operations. When getting denied to tunnel the specific protocols SMB or TELNET, curl would use a heap-allocated struct after it had been freed, in its transfer shutdown code path.
Affected products
haxx: curl; apple: macos; splunk: universal forwarder
References10
- security.netapp.com/advisory/ntap-20230214-0002/ Vendor Advisory
- security.netapp.com/advisory/ntap-20230214-0002/ Vendor Advisory
- hackerone.com/reports/1764858 ExploitIssue TrackingThird Party Advisory
- hackerone.com/reports/1764858 ExploitIssue TrackingThird Party Advisory
- seclists.org/fulldisclosure/2023/Mar/17 Mailing ListThird Party Advisory
- security.gentoo.org/glsa/202310-12 Third Party Advisory
- support.apple.com/kb/HT213670 Third Party Advisory
- seclists.org/fulldisclosure/2023/Mar/17 Mailing ListThird Party Advisory
- security.gentoo.org/glsa/202310-12 Third Party Advisory
- support.apple.com/kb/HT213670 Third Party Advisory
Metrics
- CVSS 3.1
-
5.9
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 3% percentile: 86 · as of 6 November 2026
- CWE
- CWE-416
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.