SB2026091653 - Multiple vulnerabilities in Misskey

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Main Vulnerability Database SB2026091653

SB2026091653 - Multiple vulnerabilities in Misskey

Published: September 16, 2026

Security Bulletin ID SB2026091653
CSH Severity
High
Patch available
YES
Number of vulnerabilities 7
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 14% Medium 43% Low 43%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 7 vulnerabilities.


1) Path traversal (CVE-ID: N/A)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in custom emoji ZIP import. A remote administrator can send a specially crafted HTTP request and write arbitrary files on the system, leading to arbitrary code execution.


2) Improper Control of Resource Identifiers ('Resource Injection') (CVE-ID: N/A)

CWE-ID: CWE-99 - Improper Control of Resource Identifiers ('Resource Injection')

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to confusion in value storage locations and insufficient validation of values received from clients. A remote attacker can disrupt another user's in-progress passkey and security key operations.


3) Heap-based buffer overflow (CVE-ID: N/A)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in libheif. A remote attacker can pass specially crafted data to the application, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.


4) Link following (CVE-ID: N/A)

CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')

CVSSv4: 6.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to compromise the target system.

The vulnerability exists due to insufficient validation in custom emoji ZIP import. A remote administrator can obtain the contents of files on the server host.


5) Missing Authorization (CVE-ID: N/A)

CWE-ID: CWE-862 - Missing Authorization

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass authorization checks.

The vulnerability exists due to missing authorization checks. A remote attacker can gain access to sensitive information on the target system.


6) Exposure of Sensitive Information Through Metadata (CVE-ID: N/A)

CWE-ID: CWE-1230 - Exposure of Sensitive Information Through Metadata

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to lack of proper authorization checks. A remote attacker can gain unauthorized access to sensitive information on the system.


7) Stored cross-site scripting (CVE-ID: N/A)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]


The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in email notifications. A remote attacker can inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


Remediation

Install update from vendor's website.

References