Vulnerability Name:

CVE-2019-20477 (CCN-176655)

Assigned:2019-11-13
Published:2019-11-13
Updated:2022-01-01
Summary: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.
CVSS v3 Severity:9.8 Critical (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
8.9 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
9.8 Critical (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
8.9 High (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
9.8 Critical (REDHAT CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
8.9 High (REDHAT Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
CVSS v2 Severity:7.5 High (CVSS v2 Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): Partial
Availibility (A): Partial
10.0 High (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): Complete
Integrity (I): Complete
Availibility (A): Complete
Vulnerability Type:CWE-502
Vulnerability Consequences:Gain Access
References:Source: MITRE
Type: CNA
CVE-2019-20477

Source: XF
Type: UNKNOWN
pyyaml-cve201920477-code-exec(176655)

Source: MISC
Type: Release Notes, Third Party Advisory
https://github.com/yaml/pyyaml/blob/master/CHANGES

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2020-e84e90dc4a

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2020-3162499159

Source: CCN
Type: PyYAML Web site
Welcome to PyYAML

Source: MISC
Type: Exploit, Third Party Advisory, VDB Entry
https://www.exploit-db.com/download/47655

Source: EXPLOIT-DB
Type: EXPLOIT
Offensive Security Exploit Database [11-13-2019]

Source: CCN
Type: IBM Security Bulletin 6566889 (Spectrum Discover)
Critical Vulnerabilities in libraries used by libraries that IBM Spectrum discover is using (libraries of libraries)

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2019-20477

Vulnerable Configuration:Configuration 1:
  • cpe:/a:pyyaml:pyyaml:*:*:*:*:*:*:*:* (Version >= 5.1 and <= 5.1.2)

    • Configuration 2:
  • cpe:/o:fedoraproject:fedora:30:*:*:*:*:*:*:*
  • OR cpe:/o:fedoraproject:fedora:31:*:*:*:*:*:*:*

    • Configuration RedHat 1:
  • cpe:/a:redhat:enterprise_linux:8:*:*:*:*:*:*:*

    • Configuration RedHat 2:
  • cpe:/a:redhat:enterprise_linux:8::appstream:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/a:pyyaml:pyyaml:5.1.2:*:*:*:*:*:*:*
  • OR cpe:/a:pyyaml:pyyaml:5.1:-:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    Oval Definitions
    Definition IDClassTitleLast Modified
    oval:com.redhat.rhsa:def:20204641
    P
    		RHSA-2020:4641: python38:3.8 security, bug fix, and enhancement update (Moderate)
    2020-11-04
    oval:com.ubuntu.bionic:def:2019204770000000
    V
    		CVE-2019-20477 on Ubuntu 18.04 LTS (bionic) - medium.
    2020-02-19
    oval:com.ubuntu.xenial:def:2019204770000000
    V
    		CVE-2019-20477 on Ubuntu 16.04 LTS (xenial) - medium.
    2020-02-19
    BACK
    pyyaml pyyaml *
    fedoraproject fedora 30
    fedoraproject fedora 31
    pyyaml pyyaml 5.1.2
    pyyaml pyyaml 5.1 -