CVE-2026-42261

Published: Mag 08, 2026 Last Modified: Mag 12, 2026
ExploitDB:
Other exploit source:
Google Dorks:
HIGH 7,1
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: low
User Interaction: none
Scope: unchanged
Confidentiality: high
Integrity: low
Availability: none

Description

AI Translation Available

PromptHub is an all-in-one AI toolbox for prompt, skill, and agent management. From version 0.4.9 to before version 0.5.4, apps/web/src/routes/skills.ts exposes an authenticated endpoint POST /api/skills/fetch-remote that fetches a user-supplied URL server-side and reflects the response body (up to 5 MB) back to the caller. The SSRF protection in apps/web/src/utils/remote-http.ts (isPrivateIPv6) attempts to block private/loopback destinations, but multiple alternate-but-valid IPv6 representations bypass the check. The bypasses reach any IPv4 address (loopback, RFC1918, link-local) via IPv4-mapped IPv6 in hex form, and the canonical ::1 via any representation that isn't the literal string '::1'. Any authenticated user (role: user or admin) can trigger the SSRF. On deployments configured with ALLOW_REGISTRATION=true — a supported and documented configuration — this means any internet user who can register. This issue has been patched in version 0.5.4.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0006
Percentile
0,2th
Updated

EPSS Score Trend (Last 5 Days)

20

Improper Input Validation

Stable
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Availability Confidentiality Integrity
Potential Impacts:
Dos: Crash, Exit, Or Restart Dos: Resource Consumption (Cpu) Dos: Resource Consumption (Memory) Read Memory Read Files Or Directories Modify Memory Execute Unauthorized Code Or Commands
Applicable Platforms
Technologies: AI/ML
Likelihood of Exploit: High
View CWE Details
693

Protection Mechanism Failure

Draft
Abstraction: Pillar Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control
Potential Impacts:
Bypass Protection Mechanism
Applicable Platforms
Technologies: ICS/OT, Not Technology-Specific
View CWE Details
918

Server-Side Request Forgery (SSRF)

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Access Control
Potential Impacts:
Read Application Data Execute Unauthorized Code Or Commands Bypass Protection Mechanism
Applicable Platforms
Technologies: AI/ML, Web Based, Web Server
View CWE Details
Application

Prompthub by Legeling

Product Information
Vendor Legeling
Product Prompthub
Version Range Affected
From 0.4.9 (inclusive)
To 0.5.4 (exclusive)
cpe:2.3:a:legeling:prompthub:*:*:*:*:-:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
https://github.com/legeling/PromptHub/security/advisories/G…
https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6
https://github.com/legeling/PromptHub/releases/tag/v0.5.4
https://github.com/legeling/PromptHub/releases/tag/v0.5.4
https://github.com/legeling/PromptHub/security/advisories/G…
https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6