SvelteJS SvelteKit up to 2.69.0 prototype pollution

Summaryinfo

A vulnerability was found in SvelteJS SvelteKit up to 2.69.0. It has been classified as critical. This affects an unknown function. Performing a manipulation results in prototype pollution. This vulnerability was named CVE-2026-82257. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, was found in SvelteJS SvelteKit up to 2.69.0. This affects an unknown code block. The manipulation with an unknown input leads to a prototype pollution vulnerability. CWE is classifying the issue as CWE-1321. 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

SvelteKit versions before 2.69.1 contain a prototype pollution vulnerability in remote form functions with file input fields that accept arbitrary user-controlled path names. Attackers can manipulate the deletion path to remove methods on the prototype, potentially disabling application functionality.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-82257 since 08/28/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

Upgrading to version 2.69.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-67583). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• SvelteJS

Name

• SvelteKit

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 2.36
• 2.37
• 2.38
• 2.39
• 2.40
• 2.41
• 2.42
• 2.43
• 2.44
• 2.45
• 2.46
• 2.47
• 2.48
• 2.49
• 2.50
• 2.51
• 2.52
• 2.53
• 2.54
• 2.55
• 2.56
• 2.57
• 2.58
• 2.59
• 2.60
• 2.61
• 2.62
• 2.63
• 2.64
• 2.65
• 2.66
• 2.67
• 2.68
• 2.69.0

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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