CVE-2026-5442: A heap buffer overflow vulnerability exists in the DICOM image decoder

Q: How do I fix CVE-2026-5442?

orthanc: upgrade to 1.12.11. Exact commands for each OS are on this page.

Q: Is CVE-2026-5442 being exploited?

CVE-2026-5442 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-5442 affect?

CVE-2026-5442 affects orthanc. Severity is critical (CVSS 9.8). 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

Q: How urgent is CVE-2026-5442?

Priority 51/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-5442 is a critical-severity flaw (CVSS 9.8) affecting orthanc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-787
Published	2026-04-09
Last modified	2026-10-26

Publisher (CNA): CERT/CC · Vendor: orthanc-server

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-09 15:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

orthanc-server orthanc UPGRADE

Affected: < 1.12.11

Fixed in: 1.12.11

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy orthanc || rpm -q orthanc || orthanc --version

2. UPGRADE to 1.12.11 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade orthanc

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade orthanc

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-5442?

orthanc: upgrade to 1.12.11. Exact commands for each OS are on this page.

Is CVE-2026-5442 being exploited?

CVE-2026-5442 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-5442 affect?

CVE-2026-5442 affects orthanc. Severity is critical (CVSS 9.8). 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

How urgent is CVE-2026-5442?

Priority 51/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-5443 CRITICAL 9.8 UPGRADE A heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images
CVE-2026-5445 CRITICAL 9.1 UPGRADE An out-of-bounds read vulnerability exists in the `DecodeLookupTable` function within `DicomImageDecoder.cpp`
CVE-2026-5437 HIGH 7.5 UPGRADE An out-of-bounds read vulnerability exists in `DicomStreamReader` during DICOM meta-header parsing
CVE-2026-5440 HIGH 7.5 UPGRADE A memory exhaustion vulnerability exists in the HTTP server due to unbounded use of the `Content-Length` heade
CVE-2026-5439 HIGH 7.5 UPGRADE A memory exhaustion vulnerability exists in ZIP archive processing

References

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