CVE-2021-41690Network attack vector

Memory exhaustion via unreleased file-information allocations

Published Jun 28, 2022 · Updated Nov 3, 2025

Memory exhaustion in DCMTK dcmqrdb through 3.6.6 allows remote attackers to interrupt the service through crafted DICOM requests. The program retains heap allocations for file information in the global LST variable instead of releasing them after processing affected requests. Repeated unauthenticated network requests consume process memory until dcmqrdb becomes unavailable, without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory exhaustion in DCMTK dcmqrdb through 3.6.6 allows remote attackers to interrupt the service through crafted DICOM requests. The program retains heap allocations for file information in the global LST variable instead of releasing them after processing affected requests. Repeated unauthenticated network requests consume process memory until dcmqrdb becomes unavailable, without reported data disclosure or modification.

The record

CVE
CVE-2021-41690
Published
Jun 28, 2022
Updated
Nov 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-401, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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