Grassroots DICOM (GDCM) CVE-2025-11266
MEDIUMAttack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessDeliver crafted malicious DICOM file
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DeliveryVictim opens file in GDCM-based app
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ExploitUnderflow in PixelData fragment indexing
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ExecutionOut-of-bounds write triggers segfault
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ImpactApplication crash (denial-of-service)
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires a victim to open or parse an attacker-supplied, malformed DICOM file in which the encapsulated PixelData contains crafted compressed-image fragments that cause an unsigned integer underflow in buffer indexing. Limiting factors are significant: the vector is local file input (AV:L), not network-reachable, and explicit user interaction is required (UI:A) - the malicious file must be delivered to and opened by the user within a GDCM-based application. There is no network-exposed service path and no code execution demonstrated; impact is limited to crashing the parsing application. |
| Impact | This is a genuine but low-urgency issue - a defensive-priority 'patch-in-normal-cycle' rather than an emergency. The CVSS 4.0 base score of 6.8 (medium) is driven by high availability impact (VA:H) combined with local vector and required user interaction (AV:L/UI:A), meaning the only realistic outcome is a crash/denial-of-service when a user opens a malicious file - not remote compromise. All exploitation signals agree on low real-world risk: EPSS is 0.15% (3rd percentile), there is no CISA KEV listing, and no public exploit code was identified in the provided intelligence. The impact ceiling is constrained: although CWE-787 (out-of-bounds write) can in principle enable code execution, the description explicitly characterizes the outcome as an unsigned-integer-underflow-driven segmentation fault / DoS, so there is no evidence supporting memory-corruption-to-RCE here. One note of caution: the input CVSS 4.0 vector asserts VC:L/VI:L (low confidentiality/integrity impact), but the description describes only a crash - this confidentiality/integrity claim is not substantiated by the text and should be verified with the vendor/ICS-CERT advisory before being relied upon. |
| Exploit ScenarioDerived | An attacker crafts a malformed DICOM file whose encapsulated PixelData contains manipulated compressed-image fragments and delivers it to a victim (e.g., as a medical image attachment or via an imaging workflow). When the victim opens or processes the file with an application built on GDCM, an unsigned integer underflow in buffer indexing triggers an out-of-bounds write and segmentation fault, crashing the application. No public exploit code was identified at time of analysis, and exploitation is limited to denial-of-service requiring local file access and user interaction. |
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Alert meAnalysisAIv1 – Oct 07, 2026
Parsing a malformed DICOM file with crafted encapsulated PixelData fragments in the Grassroots DICOM (GDCM) library triggers an out-of-bounds write caused by unsigned integer underflow in buffer indexing, crashing the parsing application and producing a denial-of-service condition. The flaw is only reachable through local file input (AV:L) with explicit user interaction (UI:A) - the malicious file must be delivered to and opened by a user inside a GDCM-based application, and there is no network-exposed service path and no code execution demonstrated, so impact is limited to availability. Exploitation risk is low at time of analysis: EPSS is 0.15% (3rd percentile), no CISA KEV listing exists, and no public exploit code has been identified. Vendor-released patch: GDCM v3.2.2.
RemediationAI
Upgrade to the vendor-released patch, GDCM v3.2.2 (https://github.com/malaterre/GDCM/releases/tag/v3.2.2), which contains the fix from commit 5829c95c8ac3afa9a3a3413675e948959c28a789; downstream vendors and medical device manufacturers that bundle GDCM should track CISA ICS Medical Advisory ICSMA-25-345-01 (https://www.cisa.gov/news-events/ics-medical-advisories/icsma-25-345-01) for their own patched product versions and rebuild against 3.2.2 rather than merely replacing the shared library. Until the upgrade is deployed, treat DICOM files from untrusted or external sources as hostile: gate ingestion behind a DICOM validator or re-encoder that rejects or rewrites encapsulated PixelData with inconsistent fragment lengths before the file reaches GDCM, and, where the workflow allows, disable processing of compressed/encapsulated transfer syntaxes so only native uncompressed PixelData is decoded - the trade-off is loss of support for JPEG/JPEG-LS/JPEG2000 datasets and the storage/bandwidth increase that comes with it. Run GDCM-based decoders under a least-privileged account or in a sandboxed process so an out-of-bounds write only terminates the worker instead of the host application, and monitor for repeating parser crashes as a signal of deliberate malformed-file delivery. Note that no public exploit code has been identified and exploitation requires a victim to open the crafted file, so patching can follow a normal maintenance cycle rather than an emergency change process.
Affected ProductsAI
All versions of the Grassroots DICOM (GDCM) library prior to v3.2.2 are affected, with the parsing flaw present in the encapsulated PixelData fragment handling path used by any GDCM-based DICOM viewer, archive, converter or medical device that decodes untrusted files; the vendor fix is published in GDCM v3.2.2 (https://github.com/malaterre/GDCM/releases/tag/v3.2.2) and in commit 5829c95c8ac3afa9a3a3413675e948959c28a789 (https://github.com/malaterre/GDCM/commit/5829c95c8ac3afa9a3a3413675e948959c28a789). The coordinated disclosure is documented in CISA ICS Medical Advisory ICSMA-25-345-01 (https://www.cisa.gov/news-events/ics-medical-advisories/icsma-25-345-01), mirrored in the CISA CSAF repository (https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2025/icsma-25-345-01.json), and recorded in NVD. No CPE strings were supplied with the input, so affected builds must be matched by version rather than by NVD CPE URI; third-party products that statically or dynamically link GDCM should be inventoried through their own vendor advisories.
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Technical ContextAI · show details
GDCM is an open-source C++ implementation of the DICOM medical imaging standard, widely embedded in viewers, archives, and medical device software to decode and transfer DICOM objects. The vulnerability is classified as CWE-787 (out-of-bounds write) and originates in the code path that parses encapsulated PixelData - compressed image bitstreams that DICOM encodes as a sequence of fragment items rather than a single contiguous byte array. When a fragment length or index is malformed, an unsigned integer underflow occurs while computing a buffer offset, so an index that should be near zero wraps to a very large value and the subsequent write lands outside the allocated fragment buffer, causing a segmentation fault. Because the flaw is in the low-level parser, any downstream application that links GDCM and decodes untrusted DICOM input inherits the exposure, which is why the issue was reported through the ICS medical advisory channel (ics-cert@hq.dhs.gov) covering the healthcare/medical imaging ecosystem. The provided CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:A) and the independent assessment (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) agree that this is a local-input, user-assisted crash with no confidentiality or integrity impact.
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Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
File-input trigger makes it local (AV:L) with required user interaction (UI:R); description shows only a crash, so A:H with C:N/I:N and no scope change.
Primary rating from Vendor (hq).
CVSS VectorVendor: hq
DescriptionCVE.org
An out-of-bounds write vulnerability exists in the Grassroots DICOM library (GDCM). The issue is triggered during parsing of a malformed DICOM file containing encapsulated PixelData fragments (compressed image data stored as multiple fragments). This vulnerability leads to a segmentation fault caused by an out-of-bounds memory access due to unsigned integer underflow in buffer indexing. It is exploitable via file input, simply opening a crafted malicious DICOM file is sufficient to trigger the crash, resulting in a denial-of-service condition.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Exploit-DB