Is CVE-2018-20655 in the CISA KEV catalog?

No. CVE-2018-20655 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2018-20655?

CVE-2018-20655 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2018-20655?

CVE-2018-20655 has an EPSS score of 2.20% (80th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2018-20655?

Upgrade whatsapp to 2.18.90.24 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2018-20655

CRITICALEPSS 80th pctl

9.8

CVSS v3

NVD

Description

When receiving calls using WhatsApp for iOS, a missing size check when parsing a sender-provided packet allowed for a stack-based overflow. This issue affects WhatsApp for iOS prior to v2.18.90.24 and WhatsApp Business for iOS prior to v2.18.90.24.

CWE-121Stack-based Buffer Overflow CWE-787Out-of-bounds Write

How to fix

Remediation Available

whatsappNVD

Affected:< 2.18.90.24Fixed in:2.18.90.24CVE-2018-20655derived from NVD

whatsapp businessNVD

Affected:< 2.18.90.24Fixed in:2.18.90.24CVE-2018-20655derived from NVD

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

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

2.20%probability of exploitation in 30 days

80thpercentile

Elevated risk: more likely to be exploited than 80% of all known CVEs.

References

Third-Party Advisory2

Related Vulnerabilities

Other CWE-121 (Stack-based Buffer Overflow) 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-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2009-0927	High	8.8	97%	KEV	Fix
CVE-2020-10924	High	8.8	87%	-	-
CVE-2022-20705	Critical	10.0	80%	-	-

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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 2025-09-03.