CVE-2022-21221Public exploitNetwork attack vector

Arbitrary file read via backslash path traversal

Published Mar 17, 2022 · Updated Sep 16, 2024

Path traversal in Valyala fasthttp before 1.34.0 allows remote attackers to read arbitrary files from Windows servers via ServeFile. normalizePath handled forward-slash traversal but failed to collapse URL-decoded backslash parent-directory segments before ServeFile resolved the path. The application must pass an attacker-controlled path to ServeFile; successful requests disclose readable files outside the intended root.

CVSS severity7.5
High
EPSS probability2.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Valyala fasthttp before 1.34.0 allows remote attackers to read arbitrary files from Windows servers via ServeFile. normalizePath handled forward-slash traversal but failed to collapse URL-decoded backslash parent-directory segments before ServeFile resolved the path. The application must pass an attacker-controlled path to ServeFile; successful requests disclose readable files outside the intended root.

The record

CVE
CVE-2022-21221
Published
Mar 17, 2022
Updated
Sep 16, 2024
Vendor
Valyala
Product
fasthttp
Classifications
CWE-22, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 17, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <1.34.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Valyala · fasthttpversion=unspecified <1.34.0

Published CVSS scores

7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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