Which versions of Prompts Chat are affected by CVE-2026-22665?

A case-sensitivity flaw in prompts.chat allows authenticated users to hijack existing user accounts by registering nearly-identical usernames that bypass validation controls, directly compromising…. A patch is available.

How to fix or mitigate CVE-2026-22665?

Within 24 hours: Identify all prompts.chat instances in your environment and document current deployed version. Within 7 days: Apply vendor patch (commit 1464475 or later) to all prompts.chat deployments and validate case-sensitive username uniqueness is enforced. Within 30 days: Audit user accounts created in the past 90 days for suspicious case-variant duplicates; review access logs for unauthorized profile modifications or metadata injection; enforce MFA on high-privilege accounts as compensating control pending patch application.

Prompts Chat CVE-2026-22665

Q: What is the CVSS score of CVE-2026-22665?

CVE-2026-22665 has a CVSS 4.0 base score of 8.6 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-18829 HIGH

Improper Handling of Case Sensitivity (CWE-178)

2026-04-03 VulnCheck

GHSA-pcq9-m482-5r7j

Information Disclosure Canonical Prompts Chat

8.6

CVSS 4.0 · Vendor: VulnCheck

Severity by source

Vendor (VulnCheck) PRIMARY

8.6 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from Vendor (VulnCheck) · only source for this CVE.

CVSS VectorVendor: VulnCheck

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

EUVD ID Assigned

Apr 03, 2026 - 20:45 euvd

EUVD-2026-18829

Analysis Generated

Apr 03, 2026 - 20:45 vuln.today

Patch released

Apr 03, 2026 - 20:45 nvd

Patch available

CVE Published

Apr 03, 2026 - 20:28 nvd

HIGH 8.6

DescriptionCVE.org

prompts.chat prior to commit 1464475 contains an identity confusion vulnerability due to inconsistent case-sensitive and case-insensitive handling of usernames across write and read paths, allowing attackers to create case-variant usernames that bypass uniqueness checks. Attackers can exploit non-deterministic username resolution to impersonate victim accounts, replace profile content on canonical URLs, and inject attacker-controlled metadata and content across the platform.

AnalysisAI

Identity confusion in prompts.chat (prior to commit 1464475) enables authenticated attackers to impersonate users and hijack profile URLs by creating case-variant usernames (e.g., 'Alice' vs 'alice'). Inconsistent case-handling between write and read operations allows bypass of uniqueness validation, letting attackers inject malicious content on canonical victim profiles. EPSS data not available; no public exploit identified at time of analysis, though attack complexity is low (CVSS:4.0 AC:L) requiring only low-privilege access (PR:L). VulnCheck disclosed this vulnerability with vendor patch released via GitHub commit.

Technical ContextAI

This vulnerability (CWE-178: Improper Handling of Case Sensitivity) affects prompts.chat, a web platform for sharing AI prompts. The root cause stems from architectural inconsistency where username validation at account creation enforces case-insensitive uniqueness checks, but subsequent data retrieval operations use case-sensitive lookups. This creates a race condition in identity resolution: when multiple case variants of a username exist (e.g., 'user', 'User', 'USER'), non-deterministic resolution logic may return different user records depending on query context. The CPE identifier (cpe:2.3:a:f:prompts.chat:*:*:*:*:*:*:*:*) indicates this affects the prompts.chat application from vendor 'f' (GitHub user/organization). The CVSS 4.0 vector shows network-accessible exploitation (AV:N) with low complexity (AC:L) and no attack timing constraints (AT:N), requiring low privileges (PR:L) and no user interaction (UI:N), resulting in high confidentiality and integrity impact to the vulnerable system (VC:H/VI:H) with no subsequent system impact propagation.

RemediationAI

Vendor-released patch: commit 1464475df2698fb7ccd0cdbc382b0750466f891d available at github.com/f/prompts.chat/commit/1464475df2698fb7ccd0cdbc382b0750466f891d. Administrators running self-hosted instances should immediately update to this commit or any subsequent release incorporating the fix by pulling latest changes from the upstream repository and redeploying. The patch implements consistent case-insensitive username handling across all database operations, eliminating case-variant registration and enforcing deterministic user resolution. For organizations unable to patch immediately, temporary risk reduction measures include implementing application-layer username normalization (force lowercase on registration and authentication), auditing existing user databases for case-variant duplicates and merging or removing conflicting accounts, and monitoring authentication logs for suspicious case-variant login attempts. Review pull request github.com/f/prompts.chat/pull/1098 for implementation details and verify database schema changes are applied during upgrade. No configuration workaround fully mitigates the vulnerability without code-level fixes.