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Fencer Vulns
medium 5.5

CVE-2018-11503 json

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…

published 2018-05-26 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-3532

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

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.

Patch / fix

  • discount Debian 14, Debian 13, Debian 12 2.2.4-1

debian advisories DEBIAN-CVE-2018-11503

  • discount Ubuntu 14.04 LTS 2.1.7-1+deb8u1build0.14.04.1

ubuntu advisories UBUNTU-CVE-2018-11503

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-11503 updated cvss 4.4

discount: Heap-based buffer-overflow in markdown.c:isfootnote() allows for denial of service

  • Red Hat Enterprise Linux 8 libmarkdown
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.54% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.