A double free vulnerability exists in libcurl <8.0.0 when sharing HSTS data between separate "handles". This sharing was introduced without considerations for do this sharing across separate threads but there was no indication of this fact in the documentation. Due to missing mutexes or thread locks, two threads sharing the same HSTS data could end up doing a double-free or use-after-free.
CVE-2023-27537
CVSS base score
5.9 (v3.1)
Severity
MEDIUM
Attack vector
Network
Weakness
CWE-415
Last modified
November 2, 2026
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
haxx libcurl
netapp active iq unified manager
netapp clustered data ontap
broadcom brocade fabric operating system firmware
netapp h300s firmware
netapp h500s firmware
netapp h700s firmware
netapp h410s firmware
splunk universal forwarder
References
- hackerone.com Exploit, Third Party Advisory
- security.gentoo.org Third Party Advisory
- security.netapp.com Third Party Advisory
- hackerone.com Exploit, Third Party Advisory
- security.gentoo.org Third Party Advisory
- security.netapp.com Third Party Advisory
- cert-portal.siemens.com
- cert-portal.siemens.com