How severe is CVE-2026-5442?

CVE-2026-5442 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-5442 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5442?

CVE-2026-5442 affects Orthanc-server Orthanc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5442?

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

Does CVE-2026-5442 have an EU (EUVD) identifier?

Yes. CVE-2026-5442 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20920.

When was CVE-2026-5442 published?

CVE-2026-5442 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-5442

CVE-2026-5442 is a critical-severity vulnerability in Orthanc-server Orthanc with a CVSS 3.x base score of 9.8. 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-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20920
Weakness: CWE-787
Affected product: Orthanc-server Orthanc
Published: 2026-04-09
Last modified: 2026-06-17

Description

A heap buffer overflow vulnerability exists in the DICOM image decoder. Dimension fields are encoded using Value Representation (VR) Unsigned Long (UL), instead of the expected VR Unsigned Short (US), which allows extremely large dimensions to be processed. This causes an integer overflow during frame size calculation and results in out-of-bounds memory access during image decoding.

Frequently asked questions

What is CVE-2026-5442?: A heap buffer overflow vulnerability exists in the DICOM image decoder. Dimension fields are encoded using Value Representation (VR) Unsigned Long (UL), instead of the expected VR Unsigned Short (US), which allows extremely large dimensions to be processed. This causes an integer overflow during frame size calculation and results in out-of-bounds memory access during image decoding.
How severe is CVE-2026-5442?: CVE-2026-5442 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-5442 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5442?: CVE-2026-5442 affects Orthanc-server Orthanc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5442?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-5442 have an EU (EUVD) identifier?: Yes. CVE-2026-5442 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20920.
When was CVE-2026-5442 published?: CVE-2026-5442 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (1)

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

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