CVE-2018-20573

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote...

6.5 MediumFix available

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

2.53%Up 1.9 points since Apr 14, 2021

What each source reports

NVD Score used 6.5

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: CVE-2018-20573
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness: CWE-119
Updated: 2026-11-02

CVE List No score

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: CVE-2018-20573
Updated: 2026-11-02

EUVDEUVD-2018-13127 No score

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: EUVD-2018-13127
Updated: 2026-11-02

GitHub AdvisoriesGHSA-wff4-h782-3qx9 6.5

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote...

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: GHSA-wff4-h782-3qx9
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-119
Updated: 2026-11-02

OSVAZL-7006 6.5

CVE-2018-20573 affecting package yaml-cpp for versions less than 0.6.2-6

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: AZL-7006
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSV 6.5

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: CVE-2018-20573
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

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OSVDEBIAN-CVE-2018-20573 6.5

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: DEBIAN-CVE-2018-20573
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2018-20573 6.5

The Scanner::EnsureTokensInQueue function in yaml-cpp (aka LibYaml-C++) 0.6.2 allows remote attackers to cause a denial of service (stack consumption and application crash) via a crafted YAML file.

Record: UBUNTU-CVE-2018-20573
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVopenSUSE-SU-2022:1073-1 No score

Security update for yaml-cpp

This update for yaml-cpp fixes the following issues:

CVE-2018-20573: Fixed remote DOS via a crafted YAML file in function Scanner:EnsureTokensInQueue (bsc#1121227).
CVE-2018-20574: Fixed remote DOS via a crafted YAML file in function SingleDocParser:HandleFlowMap (bsc#1121230).
CVE-2019-6285: Fixed remote DOS via a crafted YAML file in function SingleDocParser::HandleFlowSequence (bsc#1122004).
CVE-2019-6292: Fixed DOS by stack consumption in singledocparser.cpp (bsc#1122021).

Record: openSUSE-SU-2022:1073-1
Updated: 2026-11-02

OSVSUSE-SU-2022:1072-1 No score

Security update for yaml-cpp

This update for yaml-cpp fixes the following issues:

CVE-2018-20573: Fixed remote DOS via a crafted YAML file in function Scanner:EnsureTokensInQueue (bsc#1121227).
CVE-2018-20574: Fixed remote DOS via a crafted YAML file in function SingleDocParser:HandleFlowMap (bsc#1121230).
CVE-2019-6285: Fixed remote DOS via a crafted YAML file in function SingleDocParser::HandleFlowSequence (bsc#1122004).
CVE-2019-6292: Fixed DOS by stack consumption in singledocparser.cpp (bsc#1122021).

Record: SUSE-SU-2022:1072-1
Updated: 2026-11-02

OSVSUSE-SU-2022:1073-1 No score

Security update for yaml-cpp

This update for yaml-cpp fixes the following issues:

CVE-2018-20573: Fixed remote DOS via a crafted YAML file in function Scanner:EnsureTokensInQueue (bsc#1121227).
CVE-2018-20574: Fixed remote DOS via a crafted YAML file in function SingleDocParser:HandleFlowMap (bsc#1121230).
CVE-2019-6285: Fixed remote DOS via a crafted YAML file in function SingleDocParser::HandleFlowSequence (bsc#1122004).
CVE-2019-6292: Fixed DOS by stack consumption in singledocparser.cpp (bsc#1122021).

Record: SUSE-SU-2022:1073-1
Updated: 2026-11-02

OSVSUSE-SU-2022:1073-2 No score

Security update for yaml-cpp

This update for yaml-cpp fixes the following issues:

CVE-2018-20573: Fixed remote DOS via a crafted YAML file in function Scanner:EnsureTokensInQueue (bsc#1121227).
CVE-2018-20574: Fixed remote DOS via a crafted YAML file in function SingleDocParser:HandleFlowMap (bsc#1121230).
CVE-2019-6285: Fixed remote DOS via a crafted YAML file in function SingleDocParser::HandleFlowSequence (bsc#1122004).
CVE-2019-6292: Fixed DOS by stack consumption in singledocparser.cpp (bsc#1122021).

Record: SUSE-SU-2022:1073-2
Updated: 2026-11-02

OSVSUSE-SU-2023:1740-3 No score

Security update for yaml-cpp

This update for yaml-cpp fixes the following issues:

CVE-2018-20573: Fixed remote DOS via a crafted YAML file in function Scanner:EnsureTokensInQueue (bsc#1121227).
CVE-2018-20574: Fixed remote DOS via a crafted YAML file in function SingleDocParser:HandleFlowMap (bsc#1121230).
CVE-2019-6285: Fixed remote DOS via a crafted YAML file in function SingleDocParser::HandleFlowSequence (bsc#1122004).
CVE-2019-6292: Fixed DOS by stack consumption in singledocparser.cpp (bsc#1122021).

Record: SUSE-SU-2023:1740-3
Updated: 2026-11-02

Affected products

yaml-cpp project yaml-cpp

Affected packages

Affected packages
Package	Affected	Fixed
`yaml-cpp` Azure Linux:2	before 0.6.2-6	0.6.2-6
`yaml-cpp` Debian:12	before 0.6.3-1	0.6.3-1
`yaml-cpp` Debian:13	before 0.6.3-1	0.6.3-1
`yaml-cpp` Debian:14	before 0.6.3-1	0.6.3-1
`yaml-cpp` SUSE:Linux Enterprise Workstation Extension 12 SP5	before 0.5.3-3.6.3	0.5.3-3.6.3
`yaml-cpp` SUSE:Linux Enterprise Installer Updates 15 SP2	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Module for Basesystem 15 SP3	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Module for Desktop Applications 15 SP3	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Real Time 15 SP2	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Micro 5.0	before 0.6.1-4.5.1	0.6.1-4.5.1

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Affected packages
Package	Affected	Fixed
`yaml-cpp` SUSE:Linux Enterprise Micro 5.1	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Micro 5.2	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Server 15 SP2-LTSS	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Linux Enterprise Server for SAP Applications 15 SP2	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` SUSE:Enterprise Storage 7	before 0.6.1-4.5.1	0.6.1-4.5.1
`yaml-cpp` Ubuntu:14.04:LTS	All versions, plus listed versions 0.3.0-10.5.1-1	None known
`yaml-cpp` Ubuntu:16.04:LTS	All versions, plus listed versions 0.5.2-20.5.2-30.5.2-4ubuntu1~16.04.4	None known
`yaml-cpp0.3` Ubuntu:16.04:LTS	All versions, plus listed versions 0.3.0-1.2	None known
`yaml-cpp` Ubuntu:18.04:LTS	All versions, plus listed versions 0.5.2-4ubuntu1	None known
`yaml-cpp0.3` Ubuntu:18.04:LTS	All versions, plus listed versions 0.3.0-1.2	None known
`yaml-cpp` Ubuntu:20.04:LTS	All versions, plus listed versions 0.6.2-4fakesync10.6.2-4ubuntu1	None known
`yaml-cpp` openSUSE:Leap 15.3	before 0.6.1-4.5.1	0.6.1-4.5.1

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

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

In short

CVE-2018-20573 is a medium vulnerability (CVSS 6.5) in Yaml-cpp Project Yaml-cpp, published December 28, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.53%, the 84th percentile. Fixed in yaml-cpp 0.6.2-6.

References

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