Security readout for executives and security teams
Plain-English summary
A vulnerable SvelteKit feature can be abused to make a server consume excessive memory and become unavailable. This affects SvelteKit 2.49.0 through 2.49.4 when the experimental form remote function is in use. The issue is fixed in 2.49.5.
Executive priority
Treat as a high-priority availability risk for affected public SvelteKit services. Patch quickly where the vulnerable experimental feature is used, especially on customer-facing systems with limited memory headroom.
Technical view
CVE-2026-22803 is a CWE-789 memory allocation flaw in SvelteKit’s experimental form remote function binary deserializer. A specially crafted submitted payload can trigger large server-side memory allocation, causing denial of service. CVSS v4.0 is 8.2, with network attack vector, low complexity, no privileges, and no user interaction.
Likely exposure
Exposure is most likely for internet-facing SvelteKit applications running @sveltejs/kit versions 2.49.0 to before 2.49.5 and using the experimental form remote function. Applications not using that feature may not be practically exposed, based on the available sources.
Exploitation context
The sources describe a remotely triggerable denial-of-service condition, not data theft or code execution. The CVE record is not marked KEV, and the provided sources do not state active exploitation in the wild.
Researcher notes
The public record identifies affected versions, vulnerable component, CWE-789, and fixed version. It does not provide evidence of active exploitation. Avoid assuming broader SvelteKit impact beyond versions 2.49.0 to 2.49.4 and use of the experimental form remote function.
Mitigation direction
- Upgrade @sveltejs/kit to version 2.49.5 or later.
- Identify and prioritize internet-facing applications using SvelteKit remote functions.
- If immediate upgrade is not possible, review vendor guidance for temporary mitigations.
- Monitor application memory and availability until patched.
Validation and detection
- Check package manifests and lockfiles for @sveltejs/kit versions 2.49.0 through 2.49.4.
- Confirm whether experimental form remote functions are enabled or used.
- Verify production deployments include @sveltejs/kit 2.49.5 or later.
- Review service monitoring for unusual memory exhaustion or restart patterns.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-789: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-22803 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.2 (4.0)
- Known Exploited
- No
- Published
Vector: 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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
8.2HighVector: 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
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/sveltejs/kit/security/advisories/GHSA-j2f3-wq62-6q46CVE reference · x_refsource_CONFIRM
- https://github.com/sveltejs/kit/commit/8ed8155215b9a74012fecffb942ad9a793b274e5CVE reference · x_refsource_MISC
- https://github.com/sveltejs/kit/releases/tag/@sveltejs%2Fadapter-node@5.5.1CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Memory Allocation with Excessive Size Value
Memory Allocation with Excessive Size Value represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.