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CVE-2018-18385

Asciidoctor Infinite Loop vulnerability

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

2.25%Up 1.6 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 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. 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.

Record
CVE-2018-18385
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness
CWE-835
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2018-18385
Updated
2026-11-02
EUVDEUVD-2022-4946 No score

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.

Record
EUVD-2022-4946
Updated
2026-11-03
GitHub AdvisoriesGHSA-qc9p-mjxm-j2wj 7.5

Asciidoctor Infinite Loop vulnerability

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.

Record
GHSA-qc9p-mjxm-j2wj
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-835
Updated
2026-11-02
OSV 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. 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.

Record
CVE-2018-18385
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2018-18385 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. 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.

Record
DEBIAN-CVE-2018-18385
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVGHSA-qc9p-mjxm-j2wj 7.5

Asciidoctor Infinite Loop vulnerability

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.

Record
GHSA-qc9p-mjxm-j2wj
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-835
Updated
2026-11-02
OSVUBUNTU-CVE-2018-18385 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. 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.

Record
UBUNTU-CVE-2018-18385
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
asciidoctor
RubyGems
before 1.5.8
1.5.8
asciidoctor
Debian:12
before 1.5.8-1
1.5.8-1
asciidoctor
Debian:13
before 1.5.8-1
1.5.8-1
asciidoctor
Debian:14
before 1.5.8-1
1.5.8-1
asciidoctor
RubyGems
before 1.5.8, plus listed versions
0.0.10.0.20.0.30.0.40.0.5
Show 19 moreShow less
0.0.60.0.70.0.90.1.00.1.10.1.20.1.30.1.41.5.01.5.11.5.21.5.31.5.41.5.51.5.61.5.6.11.5.6.21.5.71.5.7.1
1.5.8
asciidoctor
Ubuntu:16.04:LTS
All versions, plus listed versions
1.5.2-21.5.3-11.5.4-1
None known
asciidoctor
Ubuntu:18.04:LTS
All versions, plus listed versions
1.5.5-1
None known

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-18385 is a high vulnerability (CVSS 7.5) in Asciidoctor, published October 16, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.25%, the 83rd percentile. Fixed in asciidoctor 1.5.8.

References

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