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Fencer Vulns
high 7.5

CVE-2021-41689 json

DCMTK through 3.6.6 does not handle string copy properly.

published 2022-06-28 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-28701

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

DCMTK through 3.6.6 does not handle string copy properly. Sending specific requests to the dcmqrdb program, it would query its database and copy the result even if the result is null, which can incur a head-based overflow. 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-2021-41689

  • 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~esm1
  • 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-2021-41689

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-2021-41689 updated cvss 7.5

dcmtk: a head-based overflow may lead to 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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.94% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 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

Affected products

  • dcmtk dcmtk

Classification

Weakness

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.