PT-2023-2340 · Libcurl+3 · Libcurl+3

Published

2023-03-20

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Updated

2026-05-18

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CVE-2023-27537

CVSS v3.1

5.9

Medium

VectorAV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions libcurl versions prior to 8.0.0
Description A double free vulnerability exists in libcurl when sharing HSTS data between separate handles. This sharing was introduced without considerations for doing 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. The vulnerability may allow a remote attacker to execute a double-free or use-after-free, potentially resulting in a denial of service condition.
Recommendations For libcurl versions prior to 8.0.0, consider disabling the sharing of HSTS data between separate handles until a patch is available. As a temporary workaround, restrict access to the HSTS data to minimize the risk of exploitation. Avoid using the shared HSTS data in multi-threaded environments until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

DoS

Double Free

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Weakness Enumeration

Related Identifiers

ALT-PU-2023-1475
ALT-PU-2023-1501
ALT-PU-2023-5727
AZL-25852
AZL-25858
AZL-34603
AZL-38114
BDU:2023-02105
CLEANSTART-2026-AY18527
CLEANSTART-2026-BW46578
CLEANSTART-2026-DI23929
CLEANSTART-2026-LQ42192
CLEANSTART-2026-OF85770
CVE-2023-27537
MGASA-2023-0263
OPENSUSE-SU-2024:12812-1

Affected Products

Alt Linux
Ibm Aix
Red Os
Libcurl