High · published September 6, 2026
A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of
space (ascii code 32) immediately before the `Secure` attribute causes curl to
store the cookie without its Secure flag. The cookie might then wrongfully be
sent over plaintext HTTP on subsequent requests to the same host.
| Product | Versions | Fixed in |
|---|---|---|
| haxx/curl | ≥ 8.13.0, < 8.22.0 | 8.22.0 |