How severe is CVE-2020-1888?

CVE-2020-1888 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 none, integrity none, and availability high.

Is CVE-2020-1888 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-1888?

CVE-2020-1888 primarily affects Facebook Hhvm. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-1888?

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-2020-1888 published?

CVE-2020-1888 was published on 2020-03-03 and last updated on 2026-06-17.

CVE-2020-1888

CVE-2020-1888 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% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Facebook Hhvm
Published: 2020-03-03
Last modified: 2026-06-17

Description

Insufficient boundary checks when decoding JSON in handleBackslash reads out of bounds memory, potentially leading to DOS. This issue affects HHVM 4.45.0, 4.44.0, 4.43.0, 4.42.0, 4.41.0, 4.40.0, 4.39.0, versions between 4.33.0 and 4.38.0 (inclusive), versions between 4.9.0 and 4.32.0 (inclusive), and versions prior to 4.8.7.

Frequently asked questions

What is CVE-2020-1888?: Insufficient boundary checks when decoding JSON in handleBackslash reads out of bounds memory, potentially leading to DOS. This issue affects HHVM 4.45.0, 4.44.0, 4.43.0, 4.42.0, 4.41.0, 4.40.0, 4.39.0, versions between 4.33.0 and 4.38.0 (inclusive), versions between 4.9.0 and 4.32.0 (inclusive), and versions prior to 4.8.7.
How severe is CVE-2020-1888?: CVE-2020-1888 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 none, integrity none, and availability high.
Is CVE-2020-1888 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-1888?: CVE-2020-1888 primarily affects Facebook Hhvm. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-1888?: 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-2020-1888 published?: CVE-2020-1888 was published on 2020-03-03 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.39.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.40.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.41.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.42.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.43.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.44.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.45.0:*:*:*:*:*:*:*

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