CVE-2025-53634: Chall-Manager's HTTP Gateway have no header check timeout leading to potential slow loris attacks

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-10 · updated 2026-06-17
Weakness: CWE-770

Description

Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. The HTTP Gateway processes headers, but with no timeout set. With a slow loris attack, an attacker could cause Denial of Service (DoS). Exploitation does not require authentication nor authorization, so anyone can exploit it. It should nonetheless not be exploitable as it is highly recommended to bury Chall-Manager deep within the infrastructure due to its large capabilities, so no users could reach the system. Patch has been implemented by commit 1385bd8 and shipped in v0.1.4.

Affected products

ctfer-io chall-manager: before 0.1.4 — fixed in 0.1.4

How to fix

Upgrade to a fixed version: ctfer-io chall-manager 0.1.4. Check the vendor advisory for mitigations.

References

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