Grav CMS 2.0.1 decompression‑bomb size‑cap bypass in its ZipArchiver and GPM Installer components. The implementation checks the uncompressed size recorded in each entry’s ZIP central‑directory header, but trusts that value rather than the actual inflated stream, allowing a crafted archive to pass the system.gpm.archive.max_uncompressed_size limit while extractTo() writes the real, much larger content, filling the filesystem or exhausting inodes. This produces a denial of service that hampers server availability but does not give the attacker code execution or direct privilege escalation.

All installations of Grav CMS version 2.0.1 from the getgrav:grav vendor are affected. The vulnerability is fixed in version 2.0.2 and later, so any deployment running 2.0.1 before the upgrade is vulnerable.

With a CVSS score of 7.1, the vulnerability is considered high‑severity, but its EPSS score of less than 1 % indicates exploitation is currently rare. The flaw requires an attacker to supply a crafted archive through an administrator upload or a package source, so it is limited to trusted or compromised users, not the general public. It is not listed in CISA’s KEV catalog. An attacker who can control the upload path could trigger disk exhaustion, temporarily disrupting services, but exploitation would be constrained to the internal system or package supply chain.