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No exploitation reportedFix available

CVE-2026-33806

No exploitation reported by the sources we read.

  • Published2026-04-15
  • Fixed in5.8.5 · 5.3.2 · 4.29.1
  • WeaknessCWE-1287 · CWE-1289

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-04-1504:17CVE publishedNVD

Versions per branch

NVD · OSV
Fastify
BranchAffectedFixed in
5.x≥ 5.3.2, < 5.8.55.8.5
5.x≥ 5.0.0, < 5.3.25.3.2
4.29≥ 4.29.0, < 4.29.14.29.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As openjs, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • fastifyother versions: not affected
    Affected
    • ≥ 5.3.2, < 5.8.5fixed in 5.8.5semver

    Not affected = 5.8.5

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-04-15

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • trigger-devMinimOSall versions · fixed in 4.5.0-r0

Full record on NVD

Fix

  1. Update Fastify to 5.8.5 · 5.3.2 · 4.29.1

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionnone2026-04-15
  • CNACVSS 3.17.5known since 2026-10-23
  • CNAweakness (CWE)CWE-1287, CWE-1289known since 2026-10-23
  • FIRST EPSSEPSS score0.4 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2026-04-15

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2026-04-15
Last Modified
2026-07-15
NVD status
Modified
GitHub Advisory
GHSA-247c-9743-5963 GHSA-mg2h-6x62-wpwc

Frequently asked questions

What is CVE-2026-33806?

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.

Is CVE-2026-33806 actively exploited?

Active exploitation of CVE-2026-33806 has not been confirmed. Its EPSS score was 0.4% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-33806?

CVE-2026-33806 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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