PyYAML up to 5.3.1 full_load input validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.9$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in PyYAML up to 5.3.1. Affected by this vulnerability is the function full_load. Executing a manipulation can lead to input validation. This vulnerability appears as CVE-2020-1747. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability classified as critical was found in PyYAML up to 5.3.1. This vulnerability affects the function full_load. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A vulnerability was discovered in the PyYAML library in versions before 5.3.1, where it is susceptible to arbitrary code execution when it processes untrusted YAML files through the full_load method or with the FullLoader loader. Applications that use the library to process untrusted input may be vulnerable to this flaw. An attacker could use this flaw to execute arbitrary code on the system by abusing the python/object/new constructor.

The weakness was presented 03/24/2020 as not defined bug report (Bugzilla). The advisory is available at bugzilla.redhat.com. This vulnerability was named CVE-2020-1747 since 11/27/2019. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 240021 (TencentOS Server 3: PyYAML (TSSA-2022:0177)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (240021). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.0
VulDB Meta Temp Score: 8.9

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CNA Base Score: 9.8
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 240021
Nessus Name: TencentOS Server 3: PyYAML (TSSA-2022:0177)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Patch: github.com

Timelineinfo

11/27/2019 🔍
03/24/2020 +118 days 🔍
03/25/2020 +1 days 🔍
06/17/2025 +1910 days 🔍

Sourcesinfo

Advisory: FEDORA-2020-40c35d7b37
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2020-1747 (🔍)
GCVE (CVE): GCVE-0-2020-1747
GCVE (VulDB): GCVE-100-152218

Entryinfo

Created: 03/25/2020 10:57
Updated: 06/17/2025 15:45
Changes: 03/25/2020 10:57 (37), 03/25/2020 11:02 (11), 10/04/2020 08:24 (1), 05/11/2024 09:27 (17), 05/11/2024 09:30 (19), 06/17/2025 15:45 (8)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

 Kuh98kiDsnkCHRdXkewU (+0)
6 years ago
Working PoC here: gist.github.com/adamczi/23a3b6d4bb7b2be35e79b0667d6682e1

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