What’s Vulnerable › Vulnerabilities

CVE-2026-5440: Memory Exhaustion via Unbounded Content-Length

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% 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 memory exhaustion vulnerability exists in the HTTP server due to unbounded use of the `Content-Length` header. The server allocates memory directly based on the attacker supplied header value without enforcing an upper limit. A crafted HTTP request containing an extremely large `Content-Length` value can trigger excessive memory allocation and server termination, even without sending a request body.

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

• https://kb.cert.org/vuls/id/536588
• https://www.machinespirits.de/
• https://www.orthanc-server.com/

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