Is CVE-2019-18840 in the CISA KEV catalog?

No. CVE-2019-18840 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2019-18840?

CVE-2019-18840 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2019-18840?

CVE-2019-18840 has an EPSS score of 1.97% (78th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2019-18840?

Upgrade wolfssl on debian 11 to 4.2.0+dfsg-3 or later.

CVE & CISA-KEV Catalog

CVE-2019-18840

HIGHEPSS 78th pctl

7.5

CVSS v3

NVD

Description

In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the domain name location index is mishandled. Because a pointer is overwritten, there is an invalid free.

CWE-787Out-of-bounds Write

How to fix

Remediation Available

wolfsslDebian

Fixed in:4.2.0+dfsg-3CVE-2019-18840

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

1.97%probability of exploitation in 30 days

78thpercentile

Elevated risk: more likely to be exploited than 78% of all known CVEs.

References

Exploit1

github.com

Related Vulnerabilities

Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2023-4863	High	8.8	100%	KEV	Fix
CVE-2020-16040	Medium	6.5	100%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.