OFFIS DCMTK CVE-2026-44033

Exploitation requires the target application to parse an attacker-controlled XML document through DCMTK's bundled parser - concretely, running dcmencap to encapsulate a malicious CDA document, or any program that passes untrusted input to OFXMLParser::parseFile() or OFXMLParser::parseString(). The malicious document must contain element nesting deeper than roughly 512 levels to overflow the stack before the (post-patch) guard would trip. Limiting factors: only DCMTK 3.7.0 is affected; the vendor rates the vector as local (AV:L) with passive user interaction (UI:P), meaning some actor or workflow must feed the file to the parser; and the impact is limited to a process crash (availability only) with no code execution, data disclosure, or persistence.

This is a moderate-severity denial-of-service issue, not a code-execution or data-exposure threat. The vendor-supplied CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:P, VA:H only, VC:N/VI:N) scores 6.8 and correctly reflects that the sole impact is availability (stack exhaustion → process crash via CWE-674 uncontrolled recursion); there is no confidentiality or integrity impact. No EPSS score, no CISA KEV listing, and no public POC were provided, so exploitation signals point to no public exploit identified at time of analysis - this is a defensively-reported bug (reported by securin, fixed in commit d12e350e) rather than an actively weaponized one. The key tension is attack vector: the vendor rates it AV:L (local), yet the description notes the parser is reachable 'through any application that calls OFXMLParser::parseFile() or parseString() on untrusted input,' which in a server-side DICOM/CDA ingestion pipeline could be remotely reachable - verify the actual exposure of the specific deployment, because a network-facing XML intake path would raise real-world risk above the AV:L rating. Even then, the worst outcome is a crash of the parsing process, patchable by upgrading past 3.7.0, so this is a 'patch-in-normal-cadence' item rather than an emergency unless DCMTK sits on a critical availability path.

An attacker crafts a small XML (or CDA) document containing hundreds of thousands of deeply nested elements and submits it to an application built on DCMTK 3.7.0 - for example a tool that runs dcmencap to encapsulate a CDA document, or any service that feeds untrusted input to OFXMLParser. When the recursive ParseXMLElement() descends through the nesting, the call stack is exhausted and the process crashes, causing denial of service. No public exploit code was provided, but the trigger is trivial to reproduce given the recursive parser design visible in the patch.