CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NCVE-2026-33806
High (7.5) in fastify fastify. EPSS 0.4% chance of exploitation in the next 30 days. Fixed in fastify 4.29.1, 5.3.2, 5.8.5.
Impact:
Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped.
This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442
Patches:
Upgrade to fastify v5.8.5 or later.
Workarounds:
None. Upgrade to the patched version.
Severity
- EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 38% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-1287, CWE-1289
- Published
- Modified
- Record from
- the NVD, synced
Affected
- fastify:fastify
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-247c-9743-5963 | npm | fastify | >=5.3.2 <5.8.5 | 5.8.5 |
| GHSA-mg2h-6x62-wpwc | npm | fastify | >=5.0.0 <5.3.2 | 5.3.2 |
| GHSA-mg2h-6x62-wpwc | npm | fastify | >=4.29.0 <4.29.1 | 4.29.1 |
References
- https://cna.openjsf.org/security-advisories.html
- https://github.com/fastify/fastify/security/advisories/GHSA-mg2h-6x62-wpwc
- https://access.redhat.com/security/cve/CVE-2026-33806
- https://bugzilla.redhat.com/show_bug.cgi?id=2458596
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33806.json