CVE-2026-5438
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductOrthanc
PublishedApr 9, 2026
First seenApr 9, 2026
Weakness typeCWE-770Allocation of resources without limits
How to fix
Update
- orthanc-server orthanc1.12.11 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| orthanc-server orthanc | v < 1.12.11 | 1.12.11 |
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