CVE-2020-13131

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-07-09 · updated 2026-06-17
Weakness: CWE-125

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.

Affected products

Yubico Libykpiv: before 2.1.0 — fixed in 2.1.0
Yubico Piv Tool Manager: before 2.0.0 — fixed in 2.0.0
Yubico Yubikey Smart Card Minidriver: through 4.1.0.172

How to fix

Upgrade to a fixed version: Yubico Libykpiv 2.1.0; Yubico Piv Tool Manager 2.0.0. Check the vendor advisory for mitigations.

References

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