CVE-2018-18385: Asciidoctor in versions < 1.5.8 allows remote attackers to cause a denial of service (infinite loop)

Q: How do I fix CVE-2018-18385?

asciidoctor: upgrade to 1.5.8. Exact commands for each OS are on this page.

Q: Is CVE-2018-18385 being exploited?

CVE-2018-18385 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2018-18385 affect?

CVE-2018-18385 affects asciidoctor. Severity is high (CVSS 7.5). Asciidoctor in versions < 1.5.8 allows remote attackers to cause a denial of service (infinite loop). The loop was caused by the fact that Parser.next_block was not exhausting all the lines in the reader as the while loop expected it would.

Q: How urgent is CVE-2018-18385?

Priority 57/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2018-18385 is a high-severity flaw (CVSS 7.5) affecting asciidoctor. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Asciidoctor in versions < 1.5.8 allows remote attackers to cause a denial of service (infinite loop). The loop was caused by the fact that Parser.next_block was not exhausting all the lines in the reader as the while loop expected it would. This was happening because the regular expression that detects any list was not agreeing with the regular expression that detects a specific list type. So the line kept getting pushed back onto the reader, hen

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.2% (top 17%)
CISA exploited list	No
Weakness	CWE-835
Published	2018-10-16
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: asciidoctor

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

Am I affected?

Timeline

2018-10-16 16:50 UTCPublished CVE record published
2026-06-17 01:47 UTCUpdated Record last modified

asciidoctor asciidoctor UPGRADE

Affected: < 1.5.8

Fixed in: 1.5.8

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.5.8 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade asciidoctor

Note

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

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-2018-18385?

asciidoctor: upgrade to 1.5.8. Exact commands for each OS are on this page.

Is CVE-2018-18385 being exploited?

CVE-2018-18385 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-2018-18385 affect?

CVE-2018-18385 affects asciidoctor. Severity is high (CVSS 7.5). Asciidoctor in versions < 1.5.8 allows remote attackers to cause a denial of service (infinite loop). The loop was caused by the fact that Parser.next_block was not exhausting all the lines in the reader as the while loop expected it would.

How urgent is CVE-2018-18385?

Priority 57/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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