Asymmetric Resource Consumption (Amplification) in gosaml2 - #VU144266
Published: August 19, 2026
Vulnerability identifier: #VU144266
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-405
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to asymmetric resource consumption in SAMLServiceProvider.ValidateEncodedResponse when processing a DEFLATE-compressed XML response during round-trip validation. A remote attacker can send a specially crafted SAML response containing many tiny XML elements to cause a denial of service.
A small compressed request can expand into a size-limited XML document that triggers disproportionately large memory allocation and sustained allocator and garbage-collector pressure, and concurrent requests can exhaust server memory.
Affected software
gosaml2
Remediation
Install security update from vendor's website.
gosaml2 - update to 0.12.0