CVE Feed

    Dashboard / CVE / CVE-2026-42261

    CVE-2026-42261

    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.

    Published:May 8, 2026
    Last Modified:May 12, 2026
    EPS:May 8, 2026
    EPSS Score:0.00055
    CVSS Score:7.1

    Affected Products

    Vendor
    Legeling
    Product
    Prompthub

    Exploits

    https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-1 Accessing Functionality Not Properly Constrained by ACLs
    CAPEC-10 Buffer Overflow via Environment Variables
    CAPEC-101 Server Side Include (SSI) Injection
    CAPEC-104 Cross Zone Scripting
    CAPEC-107 Cross Site Tracing
    CAPEC-108 Command Line Execution through SQL Injection
    CAPEC-109 Object Relational Mapping Injection
    CAPEC-110 SQL Injection through SOAP Parameter Tampering
    CAPEC-120 Double Encoding
    CAPEC-127 Directory Indexing
    CAPEC-13 Subverting Environment Variable Values
    CAPEC-135 Format String Injection
    CAPEC-136 LDAP Injection
    CAPEC-14 Client-side Injection-induced Buffer Overflow
    CAPEC-153 Input Data Manipulation
    CAPEC-17 Using Malicious Files
    CAPEC-182 Flash Injection
    CAPEC-20 Encryption Brute Forcing
    CAPEC-209 XSS Using MIME Type Mismatch
    CAPEC-22 Exploiting Trust in Client
    CAPEC-23 File Content Injection
    CAPEC-230 Serialized Data with Nested Payloads
    CAPEC-231 Oversized Serialized Data Payloads
    CAPEC-237 Escaping a Sandbox by Calling Code in Another Language
    CAPEC-24 Filter Failure through Buffer Overflow
    CAPEC-250 XML Injection
    CAPEC-261 Fuzzing for garnering other adjacent user/sensitive data
    CAPEC-267 Leverage Alternate Encoding
    CAPEC-28 Fuzzing
    CAPEC-3 Using Leading 'Ghost' Character Sequences to Bypass Input Filters
    CAPEC-31 Accessing/Intercepting/Modifying HTTP Cookies
    CAPEC-36 Using Unpublished Interfaces or Functionality
    CAPEC-42 MIME Conversion
    CAPEC-43 Exploiting Multiple Input Interpretation Layers
    CAPEC-45 Buffer Overflow via Symbolic Links
    CAPEC-46 Overflow Variables and Tags
    CAPEC-47 Buffer Overflow via Parameter Expansion
    CAPEC-473 Signature Spoof
    CAPEC-477 Signature Spoofing by Mixing Signed and Unsigned Content
    CAPEC-480 Escaping Virtualization
    CAPEC-51 Poison Web Service Registry
    CAPEC-52 Embedding NULL Bytes
    CAPEC-53 Postfix, Null Terminate, and Backslash
    CAPEC-57 Utilizing REST's Trust in the System Resource to Obtain Sensitive Data
    CAPEC-588 DOM-Based XSS
    CAPEC-59 Session Credential Falsification through Prediction
    CAPEC-63 Cross-Site Scripting (XSS)
    CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic
    CAPEC-65 Sniff Application Code
    CAPEC-664 Server Side Request Forgery
    CAPEC-668 Key Negotiation of Bluetooth Attack (KNOB)
    CAPEC-67 String Format Overflow in syslog()
    CAPEC-7 Blind SQL Injection
    CAPEC-71 Using Unicode Encoding to Bypass Validation Logic
    CAPEC-72 URL Encoding
    CAPEC-73 User-Controlled Filename
    CAPEC-74 Manipulating State
    CAPEC-78 Using Escaped Slashes in Alternate Encoding
    CAPEC-79 Using Slashes in Alternate Encoding
    CAPEC-8 Buffer Overflow in an API Call
    CAPEC-80 Using UTF-8 Encoding to Bypass Validation Logic
    CAPEC-81 Web Server Logs Tampering
    CAPEC-83 XPath Injection
    CAPEC-85 AJAX Footprinting
    CAPEC-87 Forceful Browsing
    CAPEC-88 OS Command Injection
    CAPEC-9 Buffer Overflow in Local Command-Line Utilities

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High