What’s Vulnerable › Vulnerabilities

CVE-2022-21221: Directory Traversal

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-03-17 · updated 2026-06-17
• Weakness: CWE-22

Description

The package github.com/valyala/fasthttp before 1.34.0 are vulnerable to Directory Traversal via the ServeFile function, due to improper sanitization. It is possible to be exploited by using a backslash %5c character in the path. **Note:** This security issue impacts Windows users only.

Affected products

• github.com/valyala/fasthttp: before 1.34.0 — fixed in 1.34.0

How to fix

Upgrade to a fixed version: github.com/valyala/fasthttp 1.34.0. Check the vendor advisory for mitigations.

References

• https://github.com/valyala/fasthttp/commit/15262ecf3c602364639d465daba1e7f3604d00e8
• https://github.com/valyala/fasthttp/commit/6b5bc7bb304975147b4af68df54ac214ed2554c1
• https://github.com/valyala/fasthttp/issues/1226
• https://github.com/valyala/fasthttp/releases/tag/v1.34.0
• https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMVALYALAFASTHTTP-2407866
• https://github.com/valyala/fasthttp/commit/15262ecf3c602364639d465daba1e7f3604d00e8
• https://github.com/valyala/fasthttp/commit/6b5bc7bb304975147b4af68df54ac214ed2554c1
• https://github.com/valyala/fasthttp/issues/1226
• https://github.com/valyala/fasthttp/releases/tag/v1.34.0
• https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMVALYALAFASTHTTP-2407866

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