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

> Attackers can bypass authentication by spoofing the X-Forwarded-For header and uid parameter to gain administrator access to the TarsWeb console.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** GHSA-2h2x-v86q-mgw5

## What is CVE-2026-80349?

CVE-2026-80349 is a critical authentication bypass vulnerability in TarsCloud TarsWeb, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2026-80349?


## How do I fix CVE-2026-80349?

No fix has been published for CVE-2026-80349 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-80349 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-80349 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80349 and fix it if it is affected.

What it is: CVE-2026-80349 is a critical authentication bypass vulnerability in TarsCloud TarsWeb, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-80349 exists.

Affected product: TarsCloud TarsWeb. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80349/ (Markdown: https://insights.sbomify.com/CVE-2026-80349/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80349
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80349
- OSV: https://osv.dev/vulnerability/CVE-2026-80349

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80349/
Summaries are generated and may contain mistakes; the official description above is the record.