How severe is CVE-2026-5440?

CVE-2026-5440 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-5440 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5440?

CVE-2026-5440 affects Orthanc-server Orthanc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5440?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-5440 have an EU (EUVD) identifier?

Yes. CVE-2026-5440 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20917.

When was CVE-2026-5440 published?

CVE-2026-5440 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-5440

CVE-2026-5440 is a high-severity vulnerability in Orthanc-server Orthanc with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20917
Weakness: CWE-770
Affected product: Orthanc-server Orthanc
Published: 2026-04-09
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-5440?: 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.
How severe is CVE-2026-5440?: CVE-2026-5440 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-5440 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5440?: CVE-2026-5440 affects Orthanc-server Orthanc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5440?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-5440 have an EU (EUVD) identifier?: Yes. CVE-2026-5440 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20917.
When was CVE-2026-5440 published?: CVE-2026-5440 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:orthanc-server:orthanc:*:*:*:*:*:*:*:*

More vulnerabilities in Orthanc-server Orthanc

CVE-2026-5443 — Critical (CVSS 9.8): A heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images. Pixel length…
CVE-2026-5442 — Critical (CVSS 9.8): A heap buffer overflow vulnerability exists in the DICOM image decoder. Dimension fields are encoded using Value…
CVE-2025-0896 — Critical (CVSS 9.8): Orthanc server prior to version 1.5.8 does not enable basic authentication by default when remote access is enabled.…
CVE-2026-5445 — Critical (CVSS 9.1): An out-of-bounds read vulnerability exists in the `DecodeLookupTable` function within `DicomImageDecoder.cpp`. The…
CVE-2023-33466 — High (CVSS 8.8): Orthanc before 1.12.0 allows authenticated users with access to the Orthanc API to overwrite arbitrary files on the…
CVE-2026-5439 — High (CVSS 7.5): A memory exhaustion vulnerability exists in ZIP archive processing. Orthanc automatically extracts ZIP archives…

All CVEs affecting Orthanc-server Orthanc →

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities

CVE-2026-31283 — Critical (CVSS 9.8): In Totara LMS v19.1.5 and before, the forgot password API does not implement rate limiting for the target email…
CVE-2020-37067 — Critical (CVSS 9.8): Filetto 1.0 FTP server contains a denial of service vulnerability in the FEAT command processing that allows attackers…
CVE-2021-47875 — Critical (CVSS 9.8): GeoGebra CAS Calculator 6.0.631.0 contains a denial of service vulnerability that allows attackers to crash the…
CVE-2025-11832 — Critical (CVSS 9.8): Allocation of Resources Without Limits or Throttling vulnerability in Azure Access Technology BLU-IC2, Azure Access…
CVE-2024-44241 — Critical (CVSS 9.8): The issue was addressed with improved bounds checks. This issue is fixed in iOS 18.1 and iPadOS 18.1, macOS Sequoia…
CVE-2022-3439 — Critical (CVSS 9.8): Allocation of Resources Without Limits or Throttling in GitHub repository ikus060/rdiffweb prior to 2.5.0.

Browse all CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities →