CVE-2019-11340 Matrix Sydent mishandles emails

What is CVE-2019-11340?

CVE-2019-11340 is a medium-severity authentication bypass vulnerability in n/a, published on 19 Apr 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

util/emailutils.py in Matrix Sydent before 1.0.2 mishandles registration restrictions that are based on e-mail domain, if the allowed_local_3pids option is enabled. This occurs because of potentially unwanted behavior in Python, in which an email.utils.parseaddr call on [email protected]@good.example.com returns the [email protected] substring.

Weakness: CWE-20

Which versions are affected by CVE-2019-11340?

3 open source packages ship an affected version, including matrix-sydent. It affects 1 product.

Products include Matrix Sydent.

How do I fix CVE-2019-11340?

Upgrade matrix-sydent to 1.0.2 or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2019-11340 being exploited?

There is no known exploitation of CVE-2019-11340 in the wild and no public exploit code.

Other vulnerabilities in n/a

• CVE-2023-38686 Sydent does not verify email server certificates Critical 9.3
• CVE-2021-29431 SSRF in Sydent due to missing validation of hostnames High 7.7
• CVE-2021-29430 Denial of service attack via memory exhaustion High 7.5
• CVE-2019-11842 matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG High 7.5
• CVE-2021-29432 Malicious users could control the content of invitation emails Medium 5.3

Sources

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

Also known as GHSA-q9h8-gpw5-c95c, PYSEC-2026-843.