# CVE-2021-42841: Cross-site scripting in n/a

> Remote attackers can execute scripts via crafted URLs to steal cookie-based authentication credentials in Insta HMS.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Jan 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-p7q5-gpw3-mqfx

## What is CVE-2021-42841?

CVE-2021-42841 is a medium-severity cross-site scripting vulnerability in n/a, published on 6 Jan 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Insta HMS before 12.4.10 is vulnerable to XSS because of improper validation of user-supplied input by multiple scripts. A remote attacker could exploit this vulnerability via a crafted URL to execute script in a victim's Web browser within the security context of the hosting Web site, once the URL is clicked. An attacker could use this vulnerability to steal the victim's cookie-based authentication credentials.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2021-42841?

It affects 1 product.


Products: Practo Insta Hms.

## How do I fix CVE-2021-42841?

No fix has been published for CVE-2021-42841 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42841 being exploited?

There is no known exploitation of CVE-2021-42841 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42841 and fix it if it is affected.

What it is: CVE-2021-42841 is a medium-severity cross-site scripting vulnerability in n/a, published on 6 Jan 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-42841 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-2021-42841/ (Markdown: https://insights.sbomify.com/CVE-2021-42841/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42841
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42841
- OSV: https://osv.dev/vulnerability/CVE-2021-42841

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42841/
Summaries are generated and may contain mistakes; the official description above is the record.