CVE-2021-23772Public exploitNetwork attack vector

Arbitrary file write via incomplete path sanitization

Published Dec 24, 2021 · Updated Sep 16, 2024

Directory traversal in Kataras Iris allows remote authenticated users to write files outside the configured upload directory. UploadFormFiles removes ../ and ..\ substrings in one pass rather than reducing each client-supplied filename to its base component, so overlapping traversal sequences survive. Exploitation requires an application route that calls UploadFormFiles and a build made with Go before 1.17; the attacker can overwrite files writable by the service account.

CVSS severity7.5
High
EPSS probability1.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Directory traversal in Kataras Iris allows remote authenticated users to write files outside the configured upload directory. UploadFormFiles removes ../ and ..\ substrings in one pass rather than reducing each client-supplied filename to its base component, so overlapping traversal sequences survive. Exploitation requires an application route that calls UploadFormFiles and a build made with Go before 1.17; the attacker can overwrite files writable by the service account.

The record

CVE
CVE-2021-23772
Published
Dec 24, 2021
Updated
Sep 16, 2024
Vendor
Kataras
Product
Iris
Classifications
CWE-59, T1105
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 24, 2021CVE 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=0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Kataras · Irisversion=0 <unspecified

Published CVSS scores

7.5SnykCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
T1105Ingress Tool Transfer

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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