CVE-2018-11503 Memory corruption in n/a

What is CVE-2018-11503?

CVE-2018-11503 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 26 May 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

The isfootnote function in markdown.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted file, as demonstrated by mkd2html.

Weakness: CWE-125

Which versions are affected by CVE-2018-11503?

It affects 2 products.

Products include Debian Debian Linux, Discount Project Discount.

How do I fix CVE-2018-11503?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2018-11503 being exploited?

There is no known exploitation of CVE-2018-11503 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-2018-11503, GHSA-3g9x-rvrx-gr8q, UBUNTU-CVE-2018-11503.