An out-of-bounds read (buffer over-read) vulnerability in the HTTP Cache-Control response header parsing of the Qt Framework (QtNetwork module) has been discovered and has been assigned the CVE id CVE-2026-76151.
Affected versions: From Qt 6.0.0 to 6.8.8, From 6.9.0 to 6.11.1
Impact: An untrusted or compromised HTTP server can cause an application using QNetworkAccessManager to terminate unexpectedly by returning an excessively large Cache-Control header value. This affects only the client side of the connection and does not affect 32-bit builds. The out-of-bounds access is read-only: there is no information disclosure and no code execution, and the impact is limited to a denial of service.
CVSS 4.0 Score: 4.6 / Medium
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/AU:N/R:A/U:Clear
Solution: Apply the following patch or update to 6.8.9, Qt 6.11.2, or later.
