Adobe Acrobat Reader AcroForms getItem use after free

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.9$5k-$25k0.00

Summaryinfo

A vulnerability was found in Adobe Acrobat Reader up to 2017.011.30199/2020.004.30006/2021.005.20060. It has been rated as critical. This issue affects the function getItem of the component AcroForms Handler. Performing a manipulation results in use after free. This vulnerability is identified as CVE-2021-39839. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Adobe Acrobat Reader up to 2017.011.30199/2020.004.30006/2021.005.20060 (Document Reader Software). It has been classified as critical. This affects the function getItem of the component AcroForms Handler. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability.

The weakness was released 09/30/2021 as apsb21-55. The advisory is shared at helpx.adobe.com. This vulnerability is uniquely identified as CVE-2021-39839 since 08/23/2021. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/30/2021).

Upgrading eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 6.9

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (Adobe Systems Incorporated): 🔍

CVSSv2info

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

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Timelineinfo

08/23/2021 🔍
09/30/2021 +38 days 🔍
09/30/2021 +0 days 🔍
10/04/2021 +4 days 🔍

Sourcesinfo

Vendor: adobe.com

Advisory: apsb21-55
Status: Confirmed

CVE: CVE-2021-39839 (🔍)
GCVE (CVE): GCVE-0-2021-39839
GCVE (VulDB): GCVE-100-183561

Entryinfo

Created: 09/30/2021 07:03
Updated: 10/04/2021 07:40
Changes: 09/30/2021 07:03 (52), 10/04/2021 07:40 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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