# CVE-2021-35296: Auth bypass in n/a

> Attackers can bypass administrator authentication on PTCL HG150-Ub v3.0 routers by modifying cookie values and response paths.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-6ff3-hggp-pc89

## What is CVE-2021-35296?

CVE-2021-35296 is a critical authentication bypass vulnerability in n/a, published on 4 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue in the administrator authentication panel of PTCL HG150-Ub v3.0 allows attackers to bypass authentication via modification of the cookie value and Response Path.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-35296?

It affects 1 product.


Products: Ptcl Hg150-Ub Firmware.

## How do I fix CVE-2021-35296?

No fix has been published for CVE-2021-35296 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-35296 being exploited?

There is no known exploitation of CVE-2021-35296 in the wild and no public exploit code.

Public exploit code:

- PoC of CVE-2021-35296 - PTCL Modem HG150-Ub (github_poc): https://github.com/afaq1337/CVE-2021-35296

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-35296 and fix it if it is affected.

What it is: CVE-2021-35296 is a critical authentication bypass vulnerability in n/a, published on 4 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-35296 in the wild and no public exploit code.

Affected product: n/a. 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-2021-35296/ (Markdown: https://insights.sbomify.com/CVE-2021-35296/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-35296
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-35296
- OSV: https://osv.dev/vulnerability/CVE-2021-35296

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-35296/
Summaries are generated and may contain mistakes; the official description above is the record.