Vulnerability · Published Apr 3, 2026 · Assigned by VulnCheck

CVE-2026-22665prompts.chat Identity Confusion via Case-Sensitive Username Handling

High 8.1

In plain English

A high-severity security flaw in prompts.chat from f. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.3%top 72.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
f	prompts.chat	0 – before 1464475df2698fb7ccd0cdbc382b0750466f891d

Weakness: CWE-178 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

https://github.com/f/prompts.chat/pull/1098 issue-tracking
https://github.com/f/prompts.chat/commit/1464475df2698fb7ccd0cdbc382b0750466f891d patch
https://www.vulncheck.com/advisories/prompts-chat-identity-confusion-via-case-sensitive-username-handling third-party-advisory