CVE-2023-27757Public exploitNetwork attack vector

Code execution via avatar upload type bypass

Published Mar 15, 2023 · Updated Feb 27, 2025

Arbitrary file upload in PerfreeBlog 3.1.1 allows remote attackers to execute code through a crafted avatar upload. The /admin/user/uploadImg endpoint relies on front-end image-type restrictions, allowing an intercepted request to restore a malicious filename suffix after presenting the payload as JPG. A self-registered account can reach the avatar workflow, and successful execution compromises the web application host.

CVSS severity9.8
Critical
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file upload in PerfreeBlog 3.1.1 allows remote attackers to execute code through a crafted avatar upload. The /admin/user/uploadImg endpoint relies on front-end image-type restrictions, allowing an intercepted request to restore a malicious filename suffix after presenting the payload as JPG. A self-registered account can reach the avatar workflow, and successful execution compromises the web application host.

The record

CVE
CVE-2023-27757
Published
Mar 15, 2023
Updated
Feb 27, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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-434Unrestricted Upload of File with Dangerous Type
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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