CVE-2026-123564
Published:November 08, 2026
Updated:November 09, 2026
Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.
Affected Packages
https://github.com/sveltejs/devalue.git (GITHUB):
Affected version(s) >=v1.0.0 <v5.9.3 || >=v2.0.0 <v5.9.3 || >=v3.0.1 <v5.9.3 || >=v4.0.0 <v5.9.3 || >=v5.0.0 <v5.9.3Fix Suggestion:
Update to version v5.9.3devalue (NPM):
Affected version(s) >=3.0.1 <5.9.3 || >=5.0.0 <5.9.3 || >=1.0.0 <5.9.3 || >=4.0.0 <5.9.3 || >=2.0.0 <5.9.3Fix Suggestion:
Update to version 5.9.3Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.34