GHSA-pvhg-7v4p-f5q9
Duplicate Advisory: SvelteKit before 3.0.0 Open Redirect via Enhanced Form Actions
Medium
Withdrawn Oct 23, 2026
npm
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- —
- No score published
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
- Fix
- None yet
- No fixed version published
Description
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-pfhg-q3qv-9q6r. This link is maintained to preserve external references.
Original Description
SvelteKit (@sveltejs/kit) before 3.0.0 contains an open redirect vulnerability in enhanced form actions (use:enhance) on routes accepting paths beginning with a double slash. Attackers can craft action paths starting with // that become protocol-relative URLs, causing non-redirect form results to navigate victims to attacker-controlled sites.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| @sveltejs/kit | all versions |
No fix yet |
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- Active
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- Low
- Integrity (subsequent systems)
- Low
- Availability (subsequent systems)
- None
- Exploit maturity
- Not defined
- Scope
- X
CVSS 3.1 4.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Weakness
CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
How to prevent it
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. Use a list of approved URLs or domains to be used for redirection.
- Architecture and Design: Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
- Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
- Architecture and Design: Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
- Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
References
Advisories
Other links
Timeline
- Published
- Withdrawn
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-27mw-82g8-phjj SvelteKit : XSS via untrusted cache-control header in prerendered page | Low | Also affects @sveltejs/kit |
| GHSA-pfhg-q3qv-9q6r SvelteKit: URL redirection to untrusted site via enhanced form submission | Medium | Also affects @sveltejs/kit |
| GHSA-29g2-3rmr-qm68 SvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header | Medium | Also affects @sveltejs/kit |
| GHSA-866w-xmhq-wj7x SvelteKit: Prototype pollution in file input deletion path in remote-function forms | Medium | Also affects @sveltejs/kit |
| GHSA-wqjv-9729-c5q2 SvelteKit: Big remote form function payloads can cause Node process to crash | Medium | Also affects @sveltejs/kit |
| GHSA-hgv7-v322-mmgr @sveltejs/kit: `query.batch` cross-talk | Medium | Also affects @sveltejs/kit |
| GHSA-3f6h-2hrp-w5wx @sveltejs/kit: Unvalidated redirect in handle hook causes Denial-of-Service | High | Also affects @sveltejs/kit |
| GHSA-2crg-3p73-43xp @sveltejs/adapter-node has a BODY_SIZE_LIMIT bypass | High | Also affects @sveltejs/kit |
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