What is the CVSS score of CVE-2020-13131?

CVE-2020-13131 has a CVSS 3.1 base score of 4.3 (Medium). CVSS vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2020-13131?

Yes, a public proof-of-concept exploit is available for CVE-2020-13131. Prioritise patching immediately. EPSS: 0.5%.

Libykpiv CVE-2020-13131

MEDIUM

Out-of-bounds Read (CWE-125)

2020-07-09 cve@mitre.org

Buffer Overflow Information Disclosure Libykpiv Piv Tool Manager Yubikey Smart Card Minidriver

4.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.3 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector

Physical

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

CVE Published

Jul 09, 2020 - 18:15 nvd

MEDIUM 4.3

DescriptionNVD

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.

AnalysisAI

An issue was discovered in Yubico libykpiv before 2.1.0. Rated medium severity (CVSS 4.3), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Out-of-bounds Read (CWE-125), which allows attackers to read data from memory outside the intended buffer boundaries. 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 include: Yubico Libykpiv, Yubico Piv Tool Manager, Yubico Yubikey Smart Card Minidriver. Version information: before 2.1.0..

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate array indices and buffer lengths. Use memory-safe languages. Enable AddressSanitizer during testing.