What’s Vulnerable › Vulnerabilities

CVE-2025-4476: Libsoup: null pointer dereference in libsoup may lead to denial of service

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-05-16 · updated 2026-06-30
• Weakness: CWE-476

Description

A denial-of-service vulnerability has been identified in the libsoup HTTP client library. This flaw can be triggered when a libsoup client receives a 401 (Unauthorized) HTTP response containing a specifically crafted domain parameter within the WWW-Authenticate header. Processing this malformed header can lead to a crash of the client application using libsoup. An attacker could exploit this by setting up a malicious HTTP server. If a user's application using the vulnerable libsoup library connects to this malicious server, it could result in a denial-of-service. Successful exploitation requires tricking a user's client application into connecting to the attacker's malicious server.

Affected products

• Red Hat Enterprise Linux 10: all versions
• Red Hat Enterprise Linux 8: all versions
• Red Hat Enterprise Linux 9: all versions

References

• https://access.redhat.com/security/cve/CVE-2025-4476
• https://bugzilla.redhat.com/show_bug.cgi?id=2366513
• https://gitlab.gnome.org/GNOME/libsoup/-/issues/440
• https://gitlab.gnome.org/GNOME/libsoup/-/work_items/440

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