CVE-2020-13131

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 61% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
24(Track)
EG Risk 24/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity43% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
40%
KEV
Not listed

Published

July 9, 2020

Last Modified

November 21, 2024

References (4)

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
yubico-piv-tool—2.1.1-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
yubico-piv-tool—2.1.1-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
yubico-piv-tool—2.1.1-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
yubico-piv-tool—2.1.1-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 121 total refreshes for this CVE.

  1. 2026-08-20 22:51 UTCEPSS rescore
  2. 2026-08-20 16:31 UTCOSV refresh
  3. 2026-08-19 17:00 UTCEPSS rescore
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  5. 2026-07-23 01:49 UTCEG score recompute
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  11. 2026-07-19 09:22 UTCOSV refresh
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  63. 2026-06-13 23:43 UTCOSV refresh
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  75. 2026-06-06 13:45 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2020-13131?
CVE-2020-13131 is a medium vulnerability published on July 9, 2020. 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…
When was CVE-2020-13131 disclosed?
CVE-2020-13131 was first published in the National Vulnerability Database on July 9, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-13131 actively exploited?
CVE-2020-13131 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 59.7% of all scored CVEs.
What is the CVSS score of CVE-2020-13131?
CVE-2020-13131 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2020-13131?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-13131, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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