Vulnerability · Published Aug 26, 2026 · Assigned by VulnCheck

CVE-2026-80349TarsWeb through 3.0.14 Authentication Bypass via Spoofed X-Forwarded-For and uid Parameter

Critical 9.8

In plain English

A critical-severity authentication bypass by spoofing in TarsWeb from TarsCloud. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.7%top 47.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

TarsWeb decides whether a request comes from a trusted local caller using a client-controlled header. app.js sets Koa's proxy option to true without naming which upstream proxies may be trusted and without limiting the number of forwarded hops, so the request address Koa reports is taken from the X-Forwarded-For header supplied by the caller. In midware/ssoMidware.js a single branch covers both the ignored-path list and the ignoreIps allowlist from config/loginConf.js, which contains the loopback address, and that branch assigns the effective account identity from the uid query parameter before falling through to the request without validating any ticket, cookie or password. A request carrying a forged X-Forwarded-For value naming the loopback address and a uid naming an existing account therefore reaches every route the console mounts as that account, including an administrator, with no credential of any kind. Those routes include user and role administration, service configuration, and package upload and deployment. Version 3.0.16 separates the two branches so that a match on the address allowlist assigns the configured default account rather than one named by the caller.

Affected products (as reported)

VendorProductVersions
TarsCloud TarsWeb 0 – through 3.0.14

Weakness: CWE-290 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References