CVE-2018-11504: The islist function in markdown.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a denia

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MEDIUM 5.5WATCHLISTDOWNGRADEMITIGATE

CVE-2018-11504 is a medium-severity flaw (CVSS 5.5) affecting discount, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The islist 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.

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-125
Published	2018-05-26
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · discount project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-05-26 21:29 UTCPublished CVE record published
2026-06-17 01:36 UTCUpdated Record last modified

discount project discount DOWNGRADE

Affected: 2.2.3 a

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2.3

1. Check installed version

apt-cache policy discount || rpm -q discount || discount --version

2. No fixed release: DOWNGRADE to a release before 2.2.3 (Debian / Ubuntu)

apt-cache madison discount sudo apt install discount=<VERSION_BEFORE_2.2.3> sudo apt-mark hold discount

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list discount sudo dnf downgrade discount-<VERSION_BEFORE_2.2.3> sudo dnf versionlock add discount

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-11504?

discount: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-11504 being exploited?

CVE-2018-11504 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-11504 affect?

CVE-2018-11504 affects discount, debian linux. Severity is medium (CVSS 5.5). The islist 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.

How urgent is CVE-2018-11504?

Priority 43/100. On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2018-12495 MEDIUM 5.5 DOWNGRADE MITIGATE The quoteblock function in markdown.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a d
CVE-2018-11503 MEDIUM 5.5 DOWNGRADE MITIGATE The isfootnote function in markdown.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a d
CVE-2018-11468 MEDIUM 5.5 DOWNGRADE MITIGATE The __mkd_trim_line function in mkdio.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a

References

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