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CVE-2018-16421

22
FAUCET Score

CVE-2018-16421 describes multiple buffer overflow vulnerabilities in OpenSC's libopensc/card-cac.c, specifically within the cac_get_serial_nr_from_CUID function, affecting versions prior to 0.19.0-rc1. An attacker with physical access to a system and able to supply a specially crafted smart card could trigger these overflows. This could lead to a denial of service (application crash) and potentially other unspecified impacts, with a CVSS v3 score of 6.6 (Medium) indicating high confidentiality, integrity, and availability impacts. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 0.18.0CPE matchmatch criteria
cpe:2.3:a:opensc_project:opensc:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

6.6MEDIUM

CVSS:3.0/AV:P/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
PHYSICAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
0.7
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
0.69%
Probability of exploitation in next 30 days
EPSS Percentile
49.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0069 is in the 80th percentile among its peer group of 170 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: opensc-0:0.19.0-3.el7
View patch

Vendor Advisories (1)

redhatCVE-2018-16421Moderate

opensc: Buffer overflows handling responses from CAC Cards in card-cac.c:cac_get_serial_nr_from_CUID()

Sep 12, 2018

References

access.redhat.com / errata/RHSA-2019:2154
github.com / OpenSC/OpenSC/commit/360e95d45ac4123255a4c796db96337f332160ad
PatchThird Party Advisory
github.com / OpenSC/OpenSC/releases/tag/0.19.0-rc1
PatchRelease NotesThird Party Advisory
lists.debian.org / debian-lts-announce/2019/09/msg00009.html
x41-dsec.de / lab/advisories/x41-2018-002-OpenSC
ExploitThird Party Advisory