NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
💎
💎 RubyGems
Not in CISA KEV
HIGH severity

CVE-2018-18385 — asciidoctor

HIGH

CVE-2018-18385 is a high-severity (CVSS 7.5) CWE-835 vulnerability in asciidoctor. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for asciidoctor — see the affected versions and patch details below.

Asciidoctor Infinite Loop vulnerability

Also known asGHSA-qc9p-mjxm-j2wj
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs83th percentile — riskier than 83% of all scored CVEsHighest risk
0.02%0.93%1.85%2.77%0.5%2.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
💎asciidoctor

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

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, hence causing the loop.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsasciidoctorall versions1.5.8bundle update asciidoctor --conservative

Affected Products

1 product · 1 configurations
Application
asciidoctorasciidoctor
< 1.5.8
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Asciidoctor in versions < 1.5.8 allows remote attackers to cause a denia…

github.comNVDOct 2019

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for asciidoctor, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update asciidoctor to 1.5.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-18385 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

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, hence causing the loop.
O3 Security · Impact-Aware SCA

Is CVE-2018-18385 in your dependencies?

Find it across RubyGems, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2018-18385: asciidoctor DoS — Fixed in 1.5.8