How severe is CVE-2020-13131?

CVE-2020-13131 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-13131 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-13131?

CVE-2020-13131 primarily affects Yubico Libykpiv. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-13131?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-13131 published?

CVE-2020-13131 was published on 2020-07-09 and last updated on 2026-06-17.

CVE-2020-13131

CVE-2020-13131 is a medium-severity vulnerability in Yubico Libykpiv with a CVSS 3.x base score of 4.3. 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-125.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 1.9
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Yubico Libykpiv
Published: 2020-07-09
Last modified: 2026-06-17

Description

An issue was discovered in Yubico libykpiv before 2.1.0. lib/util.c in this library (which is included in yubico-piv-tool) does not properly check embedded length fields during device communication. A malicious PIV token can misreport the returned length fields during RSA key generation. This will cause stack memory to be copied into heap allocated memory that gets returned to the caller. The leaked memory could include PINs, passwords, key material, and other sensitive information depending on the integration. During further processing by the caller, this information could leak across trust boundaries. Note that RSA key generation is triggered by the host and cannot directly be triggered by the token.

Frequently asked questions

What is CVE-2020-13131?: An issue was discovered in Yubico libykpiv before 2.1.0. lib/util.c in this library (which is included in yubico-piv-tool) does not properly check embedded length fields during device communication. A malicious PIV token can misreport the returned length fields during RSA key generation. This will cause stack memory to be copied into heap allocated memory that gets returned to the caller. The leaked memory could include PINs, passwords, key material, and other sensitive information depending on the integration. During further processing by the caller, this information could leak across trust boundaries. Note that RSA key generation is triggered by the host and cannot directly be triggered by the token.
How severe is CVE-2020-13131?: CVE-2020-13131 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-13131 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-13131?: CVE-2020-13131 primarily affects Yubico Libykpiv. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-13131?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-13131 published?: CVE-2020-13131 was published on 2020-07-09 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:yubico:libykpiv:*:*:*:*:*:*:*:*
cpe:2.3:a:yubico:piv_tool_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:yubico:yubikey_smart_card_minidriver:*:*:*:*:*:*:*:*

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