How severe is CVE-2016-6875?

CVE-2016-6875 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-2016-6875 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-2016-6875?

CVE-2016-6875 affects Facebook Hhvm. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-6875?

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-2016-6875 published?

CVE-2016-6875 was published on 2017-02-17 and last updated on 2026-06-17.

CVE-2016-6875

CVE-2016-6875 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.

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
Affected product: Facebook Hhvm
Published: 2017-02-17
Last modified: 2026-06-17

Description

Infinite recursion in wddx in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vectors.

Frequently asked questions

What is CVE-2016-6875?: Infinite recursion in wddx in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vectors.
How severe is CVE-2016-6875?: CVE-2016-6875 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-2016-6875 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-2016-6875?: CVE-2016-6875 affects Facebook Hhvm. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-6875?: 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-2016-6875 published?: CVE-2016-6875 was published on 2017-02-17 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in Facebook Hhvm

CVE-2022-36937 — Critical (CVSS 9.8): HHVM 4.172.0 and all prior versions use TLS 1.0 for secure connections when handling tls:// URLs in the stream…
CVE-2021-24036 — Critical (CVSS 9.8): Passing an attacker controlled size when creating an IOBuf could cause integer overflow, leading to an out of bounds…
CVE-2020-1900 — Critical (CVSS 9.8): When unserializing an object with dynamic properties HHVM needs to pre-reserve the full size of the dynamic property…
CVE-2021-24025 — Critical (CVSS 9.8): Due to incorrect string size calculations inside the preg_quote function, a large input string passed to the function…
CVE-2020-1917 — Critical (CVSS 9.8): xbuf_format_converter, used as part of exif_read_data, was appending a terminating null character to the generated…
CVE-2020-1916 — Critical (CVSS 9.8): An incorrect size calculation in ldap_escape may lead to an integer overflow when overly long input is passed in,…

All CVEs affecting Facebook Hhvm →