Is CVE-2020-1921 in the CISA KEV catalog?

No. CVE-2020-1921 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2020-1921?

CVE-2020-1921 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2020-1921?

CVE-2020-1921 has an EPSS score of 1.21% (65th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2020-1921?

Upgrade hhvm to 4.93.2 or later.

CVE & CISA-KEV Catalog

CVE-2020-1921

HIGH

7.5

CVSS v3

NVD

Description

In the crypt function, we attempt to null terminate a buffer using the size of the input salt without validating that the offset is within the buffer. This issue affects HHVM versions prior to 4.56.3, all versions between 4.57.0 and 4.80.1, all versions between 4.81.0 and 4.93.1, and versions 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0.

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

How to fix

Remediation Available

hhvmNVD

Affected:>= 4.81.0, < 4.93.2Fixed in:4.93.2CVE-2020-1921derived 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

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

1.21%probability of exploitation in 30 days

65thpercentile

Moderate risk: more likely to be exploited than 65% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

hhvm.com

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 2024-11-21.