DCMTK: Uncontrolled Recursion
CVE-2026-44031 is a high-severity uncontrolled recursion vulnerability in DCMTK from OFFIS, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected DCMTK versions: 3.7.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.39% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of DCMTK you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA |
| CVSS 3.1 | 7.5 | High | CNA |
Official description
Uncontrolled recursion in DcmSequenceOfItems::read() and DcmItem::read() in the dcmdata library of OFFIS DCMTK 3.7.0 allows a remote, unauthenticated attacker to cause a denial of service (stack exhaustion and process crash) via a DICOM dataset containing deeply nested sequences (SQ elements). The dataset can be sent in a C-STORE request to storescp, dcmrecv, dcmqrscp, or any other DICOM service built on DCMTK, because the received dataset is parsed before any authentication takes place. Local tools such as dcmdump also crash when opening such a file. The issue is fixed in commit 885ff0f10372bd589b5f44cea974f28a3964cb0f, which adds a configurable sequence nesting depth limit (default 64).
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Uncontrolled Recursion
The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
How developers prevent this class of flaw
- Ensure that an end condition will be reached under all logic conditions. The end condition may include checking against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
References
Patches and release notes
Other references
Other vulnerabilities in DCMTK
- 8.2 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
Recent Uncontrolled Recursion vulnerabilities
- 7.5 High severity
- 8.2 High severity
- 7.5 High severity
- 7.5 High severity
- 8.7 High severity
- 8.2 High severity
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