Route-guard bypass via unnormalized dot-dot segments
Published Jul 23, 2026 · Updated Jul 23, 2026
Path traversal in Fastify @fastify/static 10.1.0 and earlier allows remote attackers to read guarded files inside the configured static root. The getPathnameForSend helper passes non-leading raw or encoded dot-dot segments through decoding, after which @fastify/send normalizes them before its traversal guard runs. Exposure requires an application to protect static-root files with route-scoped middleware or guards; the bypass reads those files but does not escape the configured root.
Summary
What happened
Path traversal in Fastify @fastify/static 10.1.0 and earlier allows remote attackers to read guarded files inside the configured static root. The getPathnameForSend helper passes non-leading raw or encoded dot-dot segments through decoding, after which @fastify/send normalizes them before its traversal guard runs. Exposure requires an application to protect static-root files with route-scoped middleware or guards; the bypass reads those files but does not escape the configured root.
The record
- CVE
- CVE-2026-15074
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- Fastify
- Product
- @fastify/static
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- Jul 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <10.1.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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