CVE-2018-6345: facebook hhvm Heap-based Buffer Overflow
Vulnerability summary
CVE-2018-6345 is a critical (CVSS 9.8) Heap-based Buffer Overflow vulnerability in facebook hhvm. EPSS estimates a 1.75% chance of exploitation in the next 30 days, higher than 77.4% of scored vulnerabilities.
Timeline
- 15-01-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
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).
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
1.75%
Chance of exploitation in the next 30 days
Percentile
77%
Versus all other CVEs
30-day change
0.00 pp
From 1.75% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Facebook1 product
- hhvm3.30.2 | ≥ 3.30.0, < unspecified | 3.27.6 | ≥ unspecified, < 3.27.6 | ≤ 3.27.5 | ≥ 3.28.0, ≤ 3.30.1
Ubuntu1 product
- hhvmAll versions (No fix recorded)
2 vendors · 2 products
References
4 links- github.com/facebook/hhvm/commit/190ffdf6c8b1ec443be202c7d69e63a7e3da25e3X Refsource MISCPatchThird Party AdvisoryREPORT