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Fencer Vulns
high 7.5

CVE-2021-41687 json

DCMTK through 3.6.6 does not handle memory free properly.

published 2022-06-28 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-28699

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

DCMTK through 3.6.6 does not handle memory free properly. The program malloc a heap memory for parsing data, but does not free it when error in parsing. Sending specific requests to the dcmqrdb program incur the memory leak. An attacker can use it to launch a DoS attack.

Patch / fix

  • dcmtk Debian 14, Debian 13, Debian 12 3.6.7-1

debian advisories DEBIAN-CVE-2021-41687

  • dcmtk Ubuntu 20.04 LTS 3.6.4-2.1ubuntu0.1
  • dcmtk Ubuntu Pro 16.04 LTS 3.6.1~20150924-5ubuntu0.1~esm1
  • dcmtk Ubuntu Pro 18.04 LTS 3.6.2-3ubuntu0.1~esm3
  • dcmtk Ubuntu Pro 20.04 LTS 3.6.4-2.1ubuntu0.1~esm1
  • dcmtk Ubuntu Pro 22.04 LTS 3.6.6-5ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-41687

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-41687 updated cvss 7.5

dcmtk: a memory leak allows a DoS

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.84% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.