Description
curl's websocket code did not update the 32 bit mask pattern for each new outgoing frame as the specification says. Instead it used a fixed mask that persisted and was used throughout the entire connection. A predictable mask pattern allows for a malicious server to induce traffic between the two communicating parties that could be interpreted by an involved proxy (configured or transparent) as genuine, real, HTTP traffic with content and thereby poison its cache. That cached poisoned content could then be served to all users of that proxy.
Problem types
CWE-340 Generation of Predictable Numbers or Identifiers
Product status
8.15.0 (semver)
8.14.1 (semver)
8.14.0 (semver)
8.13.0 (semver)
8.12.1 (semver)
8.12.0 (semver)
8.11.1 (semver)
8.11.0 (semver)
Credits
Calvin Ruocco (Vector Informatik GmbH)
Daniel Stenberg
References
curl.se/docs/CVE-2025-10148.json (json)
curl.se/docs/CVE-2025-10148.html (www)
hackerone.com/reports/3330839 (issue)