Cyber Resilience

CVE-2023-29008

SSRF in Sveltekit ≤ 1.15.2

Published
06 April 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0037 30th percentile
Risk Priority 63 floored blend · peak EPSS

Summary

CVE-2023-29008 is a high-severity SSRF (CWE-918) vulnerability in Svelte Sveltekit. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 30th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The SvelteKit framework offers developers an option to create simple REST APIs. This is done by defining a `+server.js` file, containing endpoint handlers for different HTTP methods. SvelteKit provides out-of-the-box cross-site request forgery (CSRF) protection to its users. The protection…

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is implemented at `kit/src/runtime/server/respond.js`. While the implementation does a sufficient job of mitigating common CSRF attacks, the protection can be bypassed in versions prior to 1.15.2 by simply specifying an upper-cased `Content-Type` header value. The browser will not send uppercase characters, but this check does not block all expected CORS requests. If abused, this issue will allow malicious requests to be submitted from third-party domains, which can allow execution of operations within the context of the victim's session, and in extreme scenarios can lead to unauthorized access to users’ accounts. This may lead to all POST operations requiring authentication being allowed in the following cases: If the target site sets `SameSite=None` on its auth cookie and the user visits a malicious site in a Chromium-based browser; if the target site doesn't set the `SameSite` attribute explicitly and the user visits a malicious site with Firefox/Safari with tracking protections turned off; and/or if the user is visiting a malicious site with a very outdated browser. SvelteKit 1.15.2 contains a patch for this issue. It is also recommended to explicitly set `SameSite` to a value other than `None` on authentication cookies especially if the upgrade cannot be done in a timely manner.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-29003Same product: Svelte Sveltekit
CVE-2025-67647Same vendor: Svelte
CVE-2023-47635Shared CWE-352, CWE-918
CVE-2026-12986Shared CWE-352, CWE-918
CVE-2024-44677Shared CWE-352, CWE-918
CVE-2024-55089Shared CWE-352, CWE-918
CVE-2025-66407Shared CWE-352, CWE-918
CVE-2024-41305Shared CWE-352, CWE-918
CVE-2024-26445Shared CWE-352
CVE-2025-46568Shared CWE-918

Affected Assets

svelte
sveltekit
≤ 1.15.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V3.3.2
  • V3.5.1
  • V10.2.1
  • V1.3.6

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-352 CWE-918

Detects anomalous request patterns consistent with cross-site request forgery.

addresses: CWE-352

Awareness training educates users on avoiding untrusted links and actions that can be exploited via CSRF.

addresses: CWE-918

Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.

addresses: CWE-352

Requiring user re-entry of credentials for sensitive actions prevents automated forgery of requests without active user participation.

addresses: CWE-352

Security testing regimens explicitly include checks for missing or ineffective anti-CSRF protections in web applications.

addresses: CWE-918

Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.

addresses: CWE-918

Validates server-side URLs and resource references to block SSRF attempts.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

mitigates

By denying access to phishing or malicious sites, the control lowers the likelihood that a user will be tricked into submitting a forged request that performs an unintended action on another site.

References