CVE-2025-53633: Chall-Manager's scenario decoding process does not check for zip bombs

Vulnerability summary

CVE-2025-53633 is a critical (CVSS 9.8) vulnerability in ctfer-io chall-manager. EPSS estimates a 0.53% chance of exploitation in the next 30 days, higher than 44.7% of scored vulnerabilities.

Timeline

1. 10-07-2025
   PublishedVulnerability first disclosed.
2. 10-07-2025
   Last modifiedVulnerability information updated.

Description

Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. When decoding a scenario (i.e. a zip archive), the size of the decoded content is not checked, potentially leading to zip bombs decompression. 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 14042aa and shipped in v0.1.4.

• CWE-405Asymmetric Resource Consumption (Amplification)The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric."