GHSA-cfw5-2vxh-hr84 CVE-2026-30226
devalue has prototype pollution in devalue.parse and devalue.unflatten
- Severity
- 6.3 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.42%
- Chance of exploitation in the next 30 days. Higher than 35.95% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
- Fix
5.6.4- Upgrade devalue to this version or later
Description
In devalue v5.6.3, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion.
Affected versions
npm
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
devalue npm → 5.6.4
- npm
npm install devalue@5.6.4- yarn
yarn add devalue@5.6.4- pnpm
pnpm add devalue@5.6.4
Severity breakdown
CVSS 4.0 6.3
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- High
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- Low
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
How to prevent it
- Implementation: By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
- Architecture and Design: By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
- Implementation: When handling untrusted objects, validating using a schema can be used.
- Implementation: By using an object without prototypes (via Object.create(null) ), adding object prototype attributes by accessing the prototype via the special attributes becomes impossible, mitigating this weakness.
- Implementation: Map can be used instead of objects in most cases. If Map methods are used instead of object attributes, it is not possible to access the object prototype or modify it.
References
Advisories
Packages
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-hx4r-w6wj-j8fg devalue: Residual sparse-array CPU amplification in uneval | Medium | Also affects devalue |
| GHSA-mcm9-63f2-9j32 devalue: Repeated primitive strings cause quadratic expansion in uneval | High | Also affects devalue |
| GHSA-wf3x-273g-mvxv devalue: Sparse arrays emitted by uneval cause eager allocation when evaluated | Low | Also affects devalue |
| GHSA-r9w8-h9r3-54w4 devalue: Custom ArrayBuffer revivers can bypass typed-array allocation validation | High | Also affects devalue |
| GHSA-x5rw-q4pp-hg5g devalue: stringifyAsync can cause an unhandled rejection despite a caught returned promise | High | Also affects devalue |
| GHSA-4q55-j62x-fr9h devalue: Malformed null-prototype object keys bypass __proto__ rejection via property-key coercion | Medium | Also affects devalue |
| GHSA-j22f-vq7h-c4qm devalue: `stringify`/`uneval` serialize shared memory | High | Also affects devalue |
| GHSA-9rgm-9g3h-6x36 Svelte devalue: DoS via malformed input | Medium | Also affects devalue |
Credits: KarimPwnz, elliott-with-the-longest-name-on-github, jviide
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