HOMEVULNERABILITIESCVE-2018-6345
CRITICAL

CVE-2018-6345

CWE-122Published: January 15, 2019· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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).

NVD Source

Technical Analysis

CVE-2018-6345 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

facebook1 product(s)
hhvm
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (4)

→
https://github.com/facebook/hhvm/commit/190ffdf6c8b1ec443be202c7d69e63a7e3da25e3Patch · Third Party Advisory
→
https://hhvm.com/blog/2019/01/14/hhvm-3.30.2.htmlRelease Notes · Vendor Advisory
→
https://github.com/facebook/hhvm/commit/190ffdf6c8b1ec443be202c7d69e63a7e3da25e3Patch · Third Party Advisory
→
https://hhvm.com/blog/2019/01/14/hhvm-3.30.2.htmlRelease Notes · Vendor Advisory

Quick Facts

CVE IDCVE-2018-6345
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-122
CISA KEVNo
Affected1 vendor(s)
PublishedJan 15, 2019

Related CVEs (CWE-122)

CVE-2021-25387
10.0
CVE-2022-34819
10.0
CVE-2021-21940
10.0
CVE-2026-46752
10.0
CVE-2025-23123
10.0
CVE-2026-44050
9.9

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2018-6345 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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