How severe is CVE-2020-1919?

CVE-2020-1919 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-1919 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-1919?

CVE-2020-1919 primarily affects Facebook Hhvm. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-1919?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-1919 published?

CVE-2020-1919 was published on 2021-03-10 and last updated on 2026-06-17.

CVE-2020-1919

CVE-2020-1919 is a high-severity vulnerability in Facebook Hhvm with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Facebook Hhvm
Published: 2021-03-10
Last modified: 2026-06-17

Description

Incorrect bounds calculations in substr_compare could lead to an out-of-bounds read when the second string argument passed in is longer than the first. 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.

Frequently asked questions

What is CVE-2020-1919?: Incorrect bounds calculations in substr_compare could lead to an out-of-bounds read when the second string argument passed in is longer than the first. 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.
How severe is CVE-2020-1919?: CVE-2020-1919 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-1919 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-1919?: CVE-2020-1919 primarily affects Facebook Hhvm. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-1919?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-1919 published?: CVE-2020-1919 was published on 2021-03-10 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.94.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.95.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.96.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.97.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.98.0:*:*:*:*:*:*:*

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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