CVE-2026-12547

SoupAuthManager caches proxy authentication credentials without scoping them to the proxy authority (host:port). When the proxy configuration changes (e.g., via system settings or WPAD), cached Proxy-Authorization headers from the previous proxy are sent to the new proxy, leaking credentials.

Weakness

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.

Affected Software

Potential Mitigations

• Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
• Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/12.html
• https://cwe.mitre.org/data/definitions/217.html
• https://cwe.mitre.org/data/definitions/612.html
• https://cwe.mitre.org/data/definitions/613.html
• https://cwe.mitre.org/data/definitions/618.html
• https://cwe.mitre.org/data/definitions/619.html
• https://cwe.mitre.org/data/definitions/621.html
• https://cwe.mitre.org/data/definitions/622.html
• https://cwe.mitre.org/data/definitions/623.html

References

• https://access.redhat.com/security/cve/CVE-2026-12547
• https://bugzilla.redhat.com/show_bug.cgi?id=2489994
• https://gitlab.gnome.org/GNOME/libsoup/-/work_items/506