CVE-2026-128123: sveltejs kit · Uncaught Exception
Affects sveltejs kitSource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium : upgrade to 3.1.1 or 2.70.4 when convenient.
Data as of 13 Nov 2026, 20:05 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 5.9 |
|---|
- Patch
- Available – fixed in 3.1.1, 2.70.4, 6.0.1 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 13 Nov 2026.
What to do
Upgrade kit to 3.1.1 or 2.70.4; adapter-node to 6.0.1 or 5.5.8.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| sveltejskit | Affected
| Fixed in
|
| sveltejskit | Affected
| Fixed in
|
| @sveltejsadapter-node | Affected
| Fixed in
|
| @sveltejsadapter-node | Affected
| Fixed in
|
AI-suggested
This vulnerability is fixed in SvelteKit versions 5.5.8, 6.0.1, 3.1.1, and 2.70.4. Users should upgrade to these versions or later to remediate the issue. No additional mitigation is required once the upgrade is applied.
Description
CVE-2026-128123 is a vulnerability in SvelteKit framework versions 5.5.7 up to but not including 5.5.8 and 6.0.0-next.0 up to but not including 6.0.1, as well as versions >=3.0.0-next.0 <3.1.1 and <2.70.4. The issue occurs in the @sveltejs/adapter-node where an attempt to add a header to an immutable request causes the server to crash, resulting in a denial of service. This flaw is fixed in versions 5.5.8, 6.0.1, 3.1.1, and 2.70.4. The CVSS score is 5.9, indicating a medium severity impact primarily due to availability disruption.
References
- github.com/sveltejs/kit/security/advisories/GHSA-rqw3-x7hx-mm3p (opens in a new tab)
- github.com/sveltejs/kit/pull/17620 (opens in a new tab)
- github.com/sveltejs/kit/commit/04756a1f7a4f73e34f1934895340a46de84fc164 (opens in a new tab)
- github.com/sveltejs/kit/commit/0a2e58cbccdd46cac20aa5af4e2edf17e0da11dd (opens in a new tab)
- github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-node@5.5.8 (opens in a new tab)
- github.com/sveltejs/kit/releases/tag/@sveltejs/adapter-node@6.0.1 (opens in a new tab)