VulnerabilityAnalyzed
CVE-2026-5438
A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`.
HIGH 7.5EPSS 0.48%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.48% probability · 40th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-770
- Affected
- orthanc-server/orthanc
- Source
- cret@cert.org
References
- https://kb.cert.org/vuls/id/536588Third Party Advisory, VDB Entry
- https://www.machinespirits.de/Not Applicable
- https://www.orthanc-server.com/Product
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.