How severe is CVE-2021-34193?

CVE-2021-34193 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-34193 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34193?

CVE-2021-34193 affects Opensc Project Opensc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34193?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-34193 published?

CVE-2021-34193 was published on 2023-08-22 and last updated on 2026-06-17.

CVE-2021-34193

CVE-2021-34193 is a high-severity vulnerability in Opensc Project Opensc with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Opensc Project Opensc
Published: 2023-08-22
Last modified: 2026-06-17

Description

Stack overflow vulnerability in OpenSC smart card middleware before 0.23 via crafted responses to APDUs.

Frequently asked questions

What is CVE-2021-34193?: Stack overflow vulnerability in OpenSC smart card middleware before 0.23 via crafted responses to APDUs.
How severe is CVE-2021-34193?: CVE-2021-34193 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-34193 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34193?: CVE-2021-34193 affects Opensc Project Opensc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34193?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-34193 published?: CVE-2021-34193 was published on 2023-08-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:opensc_project:opensc:*:*:*:*:*:*:*:*

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CVE-2018-16393 — Medium (CVSS 6.8): Several buffer overflows when handling responses from a Gemsafe V1 Smartcard in gemsafe_get_cert_len in…
CVE-2018-16392 — Medium (CVSS 6.8): Several buffer overflows when handling responses from a TCOS Card in tcos_select_file in libopensc/card-tcos.c in…

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