CVE-2018-6334

CRITICAL
9.8
CVSS Score
Published: December 31, 2018 at 08:00 PM UTC
Updated: June 17, 2026 at 02:01 AM UTC
1 product affected across 1 vendorHHVM

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Severity
CRITICAL9.8
Exploit prediction
EPSS 2%
SSVC
No known exploit

Description

Multipart-file uploads call variables to be improperly registered in the global scope. In cases where variables are not declared explicitly before being used this can lead to unexpected behavior. This affects all supported versions of HHVM prior to the patch (3.25.1, 3.24.5, and 3.21.9 and below).

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 3.21.9v < 3.21.103.21.10 ≤ v ≤ 3.24.53.24.6 ≤ v ≤ 3.25.13.21.103.22.03.24.63.25.03.25.2
Affected range stops below 3.21.10, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

SSVC — Action Prioritization

SSVCNo known exploitAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

9.8CRITICALCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-621CWE-20

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