CVE-2023-38039: Fedoraproject Fedora

High severity, CVSS 7.5. EPSS: 58.1% chance of exploitation in the next 30 days.

When curl retrieves an HTTP response, it stores the incoming headers so that they can be accessed later via the libcurl headers API. However, curl did not have a limit in how many or how large headers it would accept in a response, allowing a malicious server to stream an endless series of headers and eventually cause curl to run out of heap memory.

Affected products

• Fedoraproject Fedora: version 37 only; version 38 only; version 39 only
• Haxx Curl: from 7.84.0, before 8.3.0 (fixed in 8.3.0)
• Microsoft Windows 10 1809: before 10.0.17763.5122 (fixed in 10.0.17763.5122)
• Microsoft Windows 10 21h2: before 10.0.19044.3693 (fixed in 10.0.19044.3693)
• Microsoft Windows 10 22h2: before 10.0.19045.3693 (fixed in 10.0.19045.3693)
• Microsoft Windows 11 21h2: before 10.0.22000.2600 (fixed in 10.0.22000.2600)
• Microsoft Windows 11 22h2: before 10.0.22621.2715 (fixed in 10.0.22621.2715)
• Microsoft Windows 11 23h2: before 10.0.22631.2715 (fixed in 10.0.22631.2715)
• Microsoft Windows Server 2019: before 10.0.17763.5122 (fixed in 10.0.17763.5122)
• Microsoft Windows Server 2022: before 10.0.20348.2113 (fixed in 10.0.20348.2113)

Published 2023-09-15. Last modified 2026-06-17.