CVE-2026-67354 – guzzlehttp/guzzle before 7.15.1 URI Fragment Disclosure via Referer

CVE ID :CVE-2026-67354

Published : Aug. 1, 2026, 1:17 p.m. | 32 minutes ago

Description :guzzlehttp/guzzle versions before 7.15.1 contain an information disclosure vulnerability in RedirectMiddleware. When the optional allow_redirects.referer setting is enabled, the middleware copies the URI fragment (the portion after ‘#’) from the referring request into the generated Referer header when following a same-scheme redirect (e.g., HTTPS to HTTPS). An attacker who controls the redirect destination can read this fragment from the incoming Referer header, potentially disclosing one-time login secrets, access tokens, state values, or other sensitive client data to a server never meant to receive it. The referer setting is disabled by default. Fixed in 7.15.1, which strips the fragment before generating the Referer value.

Severity: 8.2 | HIGH

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