CVE-2018-6345

9.8 criticalEPSS 1.7%

The function number_format is vulnerable to a heap overflow issue when its second argument ($dec_points) is excessively large. The internal implementation of the function will cause a string to be created with an invalid length, which can then interact poorly with other functions. This affects all supported versions of HHVM (3.30.1 and 3.27.5 and below).

Severity

CVSS 3.1

9.8 critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 1.7% chance of exploitation in the next 30 days; higher than 77% of CVEs (scores of 2026-10-31)
CWEs: CWE-787, CWE-122
Published: 2019-01-15
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

facebook:hhvm

References

https://github.com/facebook/hhvm/commit/190ffdf6c8b1ec443be202c7d69e63a7e3da25e3
https://hhvm.com/blog/2019/01/14/hhvm-3.30.2.html
https://github.com/facebook/hhvm/commit/190ffdf6c8b1ec443be202c7d69e63a7e3da25e3
https://hhvm.com/blog/2019/01/14/hhvm-3.30.2.html

Check your stack JSON