CVE-2025-14523: Request Smuggling (CVSS 8.2)

Description

A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a request and returns the last occurrence for server-side processing. Common front proxies often honor the first Host: header, so this mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend interprets it as destined for another host. This discrepancy enables request-smuggling style attacks, cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers.

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CVSS v3.1 Score

8.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Weakness Type (CWE)

CWE-444 CWE-444

References

Other References

https://access.redhat.com/errata/RHSA-2026:0421 https://access.redhat.com/errata/RHSA-2026:0422 https://access.redhat.com/errata/RHSA-2026:0423 https://access.redhat.com/errata/RHSA-2026:0836 https://access.redhat.com/errata/RHSA-2026:0867 https://access.redhat.com/errata/RHSA-2026:0868 https://access.redhat.com/errata/RHSA-2026:0905 https://access.redhat.com/errata/RHSA-2026:0906 https://access.redhat.com/errata/RHSA-2026:0907 https://access.redhat.com/errata/RHSA-2026:0908

Frequently Asked Questions

What is CVE-2025-14523? +

A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a request and returns the last occurrence for server-side processing. Common front proxies often honor the first Host: header, so this mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend interprets it as destined for another host. This discrepancy enables request-smuggling style attacks, cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers. It has a CVSS v3.1 base score of 8.2 (HIGH).

How severe is CVE-2025-14523? +

CVE-2025-14523 has a CVSS v3.1 score of 8.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2025-14523? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-14523