Description
PyYAML 5.1 through 5.1.2 has insufficient restrictions on the load and load_all functions because of a class deserialization issue, e.g., Popen is a class in the subprocess module. NOTE: this issue exists because of an incomplete fix for CVE-2017-18342.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pyyaml | 5.2-1 | — |
| Debian 13 | pyyaml | 5.2-1 | — |
| Debian 12 | pyyaml | 5.2-1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | Cython +1 | 0.29.14-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | PyYAML +1 | 5.3.1-1.module+el8.3.0+7187+a27ec44b | RHSA-2020:4641 |
| RHEL 8 | babel +1 | 2.7.0-10.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | mod_wsgi +1 | 4.6.8-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | numpy +3 | 1.17.3-5.module+el8.3.0+7187+a27ec44b | RHSA-2020:4641 |
| RHEL 8 | python-PyMySQL +1 | 0.9.3-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-asn1crypto +1 | 1.2.0-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-cffi +1 | 1.13.2-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-chardet +1 | 3.0.4-19.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-cryptography +1 | 2.8-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-idna +1 | 2.8-6.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-jinja2 +1 | 2.10.3-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-lxml +1 | 4.4.1-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-markupsafe +1 | 1.1.1-6.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-ply +1 | 3.11-8.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-psutil +1 | 5.6.4-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-psycopg2 +3 | 2.8.4-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-pycparser +1 | 2.19-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-pysocks +1 | 1.7.1-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-requests +1 | 2.22.0-9.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-six +1 | 1.12.0-9.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-urllib3 +1 | 1.25.7-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | python-wheel +2 | 0.33.6-5.module+el8.3.0+7187+a27ec44b | RHSA-2020:4641 |
| RHEL 8 | python38 +7 | 3.8.3-3.module+el8.3.0+7680+79e7e61a | RHSA-2020:4641 |
| RHEL 8 | python38-pip +2 | 19.3.1-1.module+el8.3.0+7187+a27ec44b | RHSA-2020:4641 |
| RHEL 8 | python38-setuptools +2 | 41.6.0-4.module+el8.3.0+7187+a27ec44b | RHSA-2020:4641 |
| RHEL 8 | pytz +1 | 2019.3-3.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
| RHEL 8 | scipy +1 | 1.3.1-4.module+el8.2.0+5234+f98739b6 | RHSA-2020:4641 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | python38-Cython | 0.29.14-4.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-asn1crypto | 1.2.0-3.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-cffi | 1.13.2-3.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-chardet | 3.0.4-19.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-cryptography | 2.8-3.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-idna | 2.8-6.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-markupsafe | 1.1.1-6.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-mod_wsgi | 4.6.8-3.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-psycopg2 +2 | 2.8.4-4.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-pycparser | 2.19-3.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-pysocks | 1.7.1-4.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-pytz | 2019.3-3.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-requests | 2.22.0-9.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
| AlmaLinux 8 | python38-scipy | 1.3.1-4.module_el8.6.0+2778+cd494b30 | ALSA-2020:4641 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | Cython | 0.29.14-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | PyYAML | 5.3.1-1.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | babel | 2.7.0-10.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | mod_wsgi | 4.6.8-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | numpy | 1.17.3-5.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-asn1crypto | 1.2.0-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-cffi | 1.13.2-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-chardet | 3.0.4-19.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-cryptography | 2.8-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-idna | 2.8-6.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-jinja2 | 2.10.3-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-markupsafe | 1.1.1-6.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-psutil | 5.6.4-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-psycopg2 | 2.8.4-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-pycparser | 2.19-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-pysocks | 1.7.1-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-requests | 2.22.0-9.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-urllib3 | 1.25.7-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python-wheel | 0.33.6-5.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python3x-pip | 19.3.1-1.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | python3x-setuptools | 41.6.0-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | pytz | 2019.3-3.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
| Rocky Linux 8 | scipy | 1.3.1-4.module+el8.4.0+570+c2eaf144 | RLSA-2020:4641 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | python38 +7 | 3.8.3-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-Cython | 0.29.14-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-PyMySQL | 0.9.3-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-asn1crypto | 1.2.0-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-babel | 2.7.0-10.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-cffi | 1.13.2-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-chardet | 3.0.4-19.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-cryptography | 2.8-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-idna | 2.8-6.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-jinja2 | 2.10.3-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-lxml | 4.4.1-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-markupsafe | 1.1.1-6.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-mod_wsgi | 4.6.8-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-numpy +2 | 1.17.3-5.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-pip +1 | 19.3.1-1.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-ply | 3.11-8.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-psutil | 5.6.4-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-psycopg2 +2 | 2.8.4-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-pycparser | 2.19-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-pysocks | 1.7.1-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-pytz | 2019.3-3.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-pyyaml | 5.3.1-1.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-requests | 2.22.0-9.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-scipy | 1.3.1-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-setuptools +1 | 41.6.0-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-six | 1.12.0-9.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-urllib3 | 1.25.7-4.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
| Oracle Linux 8 | python38-wheel +1 | 0.33.6-5.module+el8.3.0+7824+e0098946 | ELSA-2020-4641 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | pyyaml | >= 5.1, < 5.2 | 5.2 | GHSA-3pqx-4fqf-j49f |
| PyPI | pyyaml | >= 5.1, < 5.2b1 | 5.2b1 | PYSEC-2020-176 |
Advisories 4
- ALSA-2020:4641 Moderate: python38:3.8 security, bug fix, and enhancement update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2020:4641 Red Hat Security Advisory: python38:3.8 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 8, 2026
- RLSA-2020:4641 Moderate: python38:3.8 security, bug fix, and enhancement update Rocky Linux Security Advisories · Feb 4, 2026
- ELSA-2020-4641 Moderate: python38:3.8 security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 10, 2020
References
- https://github.com/yaml/pyyaml/blob/master/CHANGES
- https://www.exploit-db.com/download/47655
- FEDORA-2020-3162499159 vendor-advisory
- FEDORA-2020-e84e90dc4a vendor-advisory