What’s Vulnerable › Vulnerabilities
CVE-2026-5438: Gzip Decompression Bomb via Content-Encoding Header
- 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: 2026-04-09 · updated 2026-10-26
- Weakness: CWE-770
Description
A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`. The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.
Affected products
- orthanc-server orthanc: before 1.12.11 — fixed in 1.12.11
How to fix
Upgrade to a fixed version: orthanc-server orthanc 1.12.11. Check the vendor advisory for mitigations.
References
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