CVE-2026-35201: Discount is an implementation of John Gruber's Markdown markup language in C

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MEDIUM 5.9REMOTEUPGRADE

CVE-2026-35201 is a medium-severity flaw (CVSS 5.9) affecting rdiscount. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Discount is an implementation of John Gruber's Markdown markup language in C. From 1.3.1.1 to before 2.2.7.4, a signed length truncation bug causes an out-of-bounds read in the default Markdown parse path. Inputs larger than INT_MAX are truncated to a signed int before entering the native parser, allowing the parser to read past the end of the supplied buffer and crash the process. This vulnerability is fixed in 2.2.7.4.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-04-06
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: dafoster

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-06 20:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

dafoster rdiscount UPGRADE

Affected: >= 1.3.1.1 and < 2.2.7.4

Fixed in: 2.2.7.4

Safe to downgrade to: a release before 1.3.1.1

1. Check installed version

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

2. UPGRADE to 2.2.7.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade rdiscount

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade rdiscount

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.3.1.1 (Debian / Ubuntu)

apt-cache madison rdiscount sudo apt install rdiscount=<VERSION_BEFORE_1.3.1.1> sudo apt-mark hold rdiscount

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list rdiscount sudo dnf downgrade rdiscount-<VERSION_BEFORE_1.3.1.1> sudo dnf versionlock add rdiscount

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.

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-2026-35201?

rdiscount: upgrade to 2.2.7.4. Exact commands for each OS are on this page.

Is CVE-2026-35201 being exploited?

CVE-2026-35201 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-2026-35201 affect?

CVE-2026-35201 affects rdiscount. Severity is medium (CVSS 5.9). Discount is an implementation of John Gruber's Markdown markup language in C. From 1.3.1.1 to before 2.2.7.4, a signed length truncation bug causes an out-of-bounds read in the default Markdown parse path. Inputs larger than INT_MAX are tru

How urgent is CVE-2026-35201?

Priority 36/100. Public exploit reference; Remotely exploitable, no login, no user action

References

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