CVE-2026-5438
Gzip Decompression Bomb via Content-Encoding Header
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.
INFO
Published Date :
April 9, 2026, 3:16 p.m.
Last Modified :
April 15, 2026, 7:31 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Apply patches or updates from the vendor.
- Configure decompression limits on HTTP requests.
- Monitor memory usage during decompression.
- Validate all incoming gzip payloads.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-5438.
| URL | Resource |
|---|---|
| https://kb.cert.org/vuls/id/536588 | Third Party Advisory VDB Entry |
| https://www.machinespirits.de/ | Not Applicable |
| https://www.orthanc-server.com/ | Product |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-5438 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-5438
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-5438 vulnerability anywhere in the article.
-
Daily CyberSecurity
Critical—9 Vulnerabilities in Orthanc DICOM Servers Threaten Medical Data Integrity
A series of critical security flaws has been uncovered in Orthanc, the popular open-source “lightweight Digital Imaging and Communications in Medicine (DICOM) server used to store, process, and retrie ... Read more
The following table lists the changes that have been made to the
CVE-2026-5438 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 15, 2026
Action Type Old Value New Value Added CWE CWE-770 Added CPE Configuration OR *cpe:2.3:a:orthanc-server:orthanc:*:*:*:*:*:*:*:* versions up to (excluding) 1.12.11 Added Reference Type CERT/CC: https://kb.cert.org/vuls/id/536588 Types: Third Party Advisory, VDB Entry Added Reference Type CERT/CC: https://www.machinespirits.de/ Types: Not Applicable Added Reference Type CERT/CC: https://www.orthanc-server.com/ Types: Product -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Apr. 14, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by [email protected]
Apr. 09, 2026
Action Type Old Value New Value Added 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. Added Reference https://kb.cert.org/vuls/id/536588 Added Reference https://www.machinespirits.de/ Added Reference https://www.orthanc-server.com/