CVE-2023-6887Public exploitNetwork attack vector

Remote code execution via trailing-dot upload

Published Dec 17, 2023 · Updated Aug 27, 2024

Unrestricted file upload in Saysky ForestBlog 20220630 allows remote authenticated users to upload executable files through /admin/upload/img. UploadFileController takes the substring after the last dot as the suffix and accepts a trailing dot because the allowlist contains a period. On Windows, the filesystem removes that trailing dot, turning a name such as 1.jpg.jsp. into an executable JSP; administrative authentication and a JSP-enabled upload mapping are required.

CVSS severity6.3
Medium
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Saysky ForestBlog 20220630 allows remote authenticated users to upload executable files through /admin/upload/img. UploadFileController takes the substring after the last dot as the suffix and accepts a trailing dot because the allowlist contains a period. On Windows, the filesystem removes that trailing dot, turning a name such as 1.jpg.jsp. into an executable JSP; administrative authentication and a JSP-enabled upload mapping are required.

The record

CVE
CVE-2023-6887
Published
Dec 17, 2023
Updated
Aug 27, 2024
Vendor
Saysky
Product
ForestBlog
Classifications
CWE-434, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 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?

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  1. Affected versionversion=20220630

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Saysky · ForestBlogversion=20220630

Published CVSS scores

6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.5VulDBAV:N/AC:L/Au:S/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1505.003Web Shell

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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