How severe is CVE-2019-11935?

CVE-2019-11935 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-2019-11935 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-11935?

CVE-2019-11935 primarily affects Facebook Hhvm. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-11935?

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-2019-11935 published?

CVE-2019-11935 was published on 2019-12-04 and last updated on 2026-06-17.

CVE-2019-11935

CVE-2019-11935 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-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Facebook Hhvm
Published: 2019-12-04
Last modified: 2026-06-17

Description

Insufficient boundary checks when processing a string in mb_ereg_replace allows access to out-of-bounds memory. This issue affects HHVM versions prior to 3.30.12, all versions between 4.0.0 and 4.8.5, all versions between 4.9.0 and 4.23.1, as well as 4.24.0, 4.25.0, 4.26.0, 4.27.0, 4.28.0, and 4.28.1.

Frequently asked questions

What is CVE-2019-11935?: Insufficient boundary checks when processing a string in mb_ereg_replace allows access to out-of-bounds memory. This issue affects HHVM versions prior to 3.30.12, all versions between 4.0.0 and 4.8.5, all versions between 4.9.0 and 4.23.1, as well as 4.24.0, 4.25.0, 4.26.0, 4.27.0, 4.28.0, and 4.28.1.
How severe is CVE-2019-11935?: CVE-2019-11935 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-2019-11935 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-11935?: CVE-2019-11935 primarily affects Facebook Hhvm. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-11935?: 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-2019-11935 published?: CVE-2019-11935 was published on 2019-12-04 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.24.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.25.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.26.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.27.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.28.0:*:*:*:*:*:*:*
cpe:2.3:a:facebook:hhvm:4.28.1:*:*:*:*:*:*:*

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