What’s Vulnerable › Vulnerabilities

CVE-2026-3632: Libsoup: libsoup: http smuggling and server-side request forgery via malformed hostnames

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-17 · updated 2026-06-17
• Weakness: CWE-1286

Description

A flaw was found in libsoup, a library used by applications to send network requests. This vulnerability occurs because libsoup does not properly validate hostnames, allowing special characters to be injected into HTTP headers. A remote attacker could exploit this to perform HTTP smuggling, where they can send hidden, malicious requests alongside legitimate ones. In certain situations, this could lead to Server-Side Request Forgery (SSRF), enabling an attacker to force the server to make unauthorized requests to other internal or external systems. The impact is low, as SoupServer is not actually used in internet infrastructure.

Affected products

• GNOME libsoup: all versions
• Red Hat Enterprise Linux: 6.0, 7.0, 8.0, 9.0, 10.0

References

• https://access.redhat.com/security/cve/CVE-2026-3632
• https://bugzilla.redhat.com/show_bug.cgi?id=2445127
• https://gitlab.gnome.org/GNOME/libsoup/-/issues/483

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