CVE-2021-3694 Cross-site Scripting (XSS) - Reflected in ledgersmb/ledgersmb

What is CVE-2021-3694?

CVE-2021-3694 is a high-severity cross-site scripting vulnerability in Debian Debian Linux, published on 23 Aug 2021. 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

LedgerSMB does not sufficiently HTML-encode error messages sent to the browser. By sending a specially crafted URL to an authenticated user, this flaw can be abused for remote code execution and information disclosure.

Weakness: CWE-79

Which versions are affected by CVE-2021-3694?

It affects 2 products.

Products include Debian Debian Linux, Ledgersmb Ledgersmb.

How do I fix CVE-2021-3694?

Apply the vendor's patch.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-3694 being exploited?

There is no known exploitation of CVE-2021-3694 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-3694, GHSA-5wc4-gq9m-293h, UBUNTU-CVE-2021-3694.