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Vulnerabilities

Vulnerability · CVE-2026-2880

A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)).

Published Feb 27, 2026 · catalog updated Jun 17, 2026 · A vulnerability in @fastify/middie

Check if you run it

No confirmed exploitation is on record for CVE-2026-2880. EPSS is 0.53%. Act only if a listed version of A vulnerability in @fastify/middie is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A vulnerability in @fastify/middie).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.53%
Remediation
Version ranges on file
Affected products
cpe fastify/fastify/middie · stated fastify/middie

A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)). When Fastify router normalization options are enabled (such as ignoreDuplicateSlashes, useSemicolonDelimiter, and related trailing-slash behavior), crafted request paths may bypass middleware checks while still being routed to protected handlers.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe fastify/fastify/middieversion unspecified
  • stated fastify/middie< 9.2.0

How to fix CVE-2026-2880

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-2880. EPSS is 0.53%. Act only if a listed version of A vulnerability in @fastify/middie is installed.

Which versions are affected?

Compare what you have installed with < 9.2.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation. EPSS 0.53%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 27, 2026 · NIST NVD

    Detected

    A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)). When Fastify router normalization options are enabled (such as ignoreDuplicateSlashes, useSemicolonDelimiter, and related trailing-slash behavior), crafted request paths may bypass middleware checks while still being routed

  2. Jun 17, 2026 · NIST NVD

    Updated

    A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)). When Fastify router normalization options are enabled (such as ignoreDuplicateSlashes, useSemicolonDelimiter, and related trailing-slash behavior), crafted request paths may bypass middleware checks while still being routed

Sources

  • CVE.orgVulnerability recordCVE-2026-2880

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-2880

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-2880

    A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)). When Fastify router normalization options are enabled (such as ignoreDuplicateSlashes, useSemicolonDel

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.