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VulnerabilityPublished

CVE-2026-22803: sveltejs kit · Excessive Memory Allocation

Affects sveltejs kitSource CVE Database V5

0

Not known to be exploited · CVSS 8.2 High : upgrade to 2.49.5 soon.

Data as of 26 Oct 2026, 11:07 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.49.5
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade sveltejs kit to 2.49.5.

Affected software

ProductAffectedFixed in
sveltejskitAffected
  • >=2.49.0 <2.49.5
Fixed in
  • 2.49.5

AI-suggested

The primary mitigation is to upgrade all affected SvelteKit instances to version 2.49.5 or later, where the vulnerability is patched. Organizations should audit their web applications to identify any usage of the experimental form remote function and ensure it is updated accordingly. In addition to patching, implementing resource limits at the application and infrastructure levels can help mitigate exploitation attempts. This includes setting maximum memory allocation thresholds, employing container or process-level memory limits, and using web application firewalls (WAFs) to detect and block suspicious payloads targeting form submissions. Monitoring application logs and memory usage metrics can provide early warning signs of exploitation attempts. For critical services, consider deploying rate limiting on form submissions to reduce the risk of automated attacks. Finally, maintain an incident response plan that includes procedures for DoS attack detection and mitigation.

Description

CVE-2026-22803 is a high-severity vulnerability in SvelteKit versions 2.49.0 through 2.49.4, where a specially crafted payload targeting the experimental form remote function can cause excessive memory allocation on the server. This leads to a denial-of-service (DoS) condition via memory exhaustion. The issue arises from improper handling of binary data representing submitted form data, allowing attackers to trigger large memory allocations without authentication or user interaction. The vulnerability is fixed in version 2.49.5.

References

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