How severe is CVE-2016-6871?

CVE-2016-6871 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-6871 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6871?

CVE-2016-6871 affects Facebook Hhvm. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-6871?

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

When was CVE-2016-6871 published?

CVE-2016-6871 was published on 2017-02-17 and last updated on 2026-06-17.

CVE-2016-6871

CVE-2016-6871 is a critical-severity vulnerability in Facebook Hhvm with a CVSS 3.x base score of 9.8. 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-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Facebook Hhvm
Published: 2017-02-17
Last modified: 2026-06-17

Description

Integer overflow in bcmath in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vectors, which triggers a buffer overflow.

Frequently asked questions

What is CVE-2016-6871?: Integer overflow in bcmath in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vectors, which triggers a buffer overflow.
How severe is CVE-2016-6871?: CVE-2016-6871 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-6871 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6871?: CVE-2016-6871 affects Facebook Hhvm. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-6871?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2016-6871 published?: CVE-2016-6871 was published on 2017-02-17 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*

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