Mozilla Firefox/Firefox ESR/Thunderbird Type Interference System Object type confusion

CVSS Meta Temp Score
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CTI Interest Score
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7.9$0-$5k0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in Mozilla Firefox, Firefox ESR and Thunderbird. Affected by this vulnerability is an unknown functionality of the component Type Interference System. Such manipulation as part of Object leads to input validation. This vulnerability is documented as CVE-2019-9791. The attack can be executed remotely. Additionally, an exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Mozilla Firefox, Firefox ESR and Thunderbird (Web Browser) (affected version unknown). Affected by this issue is an unknown functionality of the component Type Interference System. The manipulation as part of a Object leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-843. The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type. Impacted is confidentiality, integrity, and availability. CVE summarizes:

The type inference system allows the compilation of functions that can cause type confusions between arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor function is entered through on-stack replacement (OSR). This allows for possible arbitrary reading and writing of objects during an exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

The bug was discovered 03/19/2019. The weakness was released 04/26/2019 by Markus Vervier (Nils) with X41 D-Sec GmbH (Website). The advisory is shared for download at access.redhat.com. This vulnerability is handled as CVE-2019-9791 since 03/14/2019. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are unknown but a public exploit is available.

The exploit is available at exploit-db.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 38 days. During that time the estimated underground price was around $5k-$25k. The commercial vulnerability scanner Qualys is able to test this issue with plugin 157940 (Oracle Enterprise Linux Security Update for firefox (ELSA-2019-0623)).

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (46613) and SecurityFocus (BID 106773†). Entries connected to this vulnerability are available at VDB-130538, VDB-134153, VDB-134155 and VDB-134157. Once again VulDB remains the best source for vulnerability data.

Productinfo

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.7

VulDB Base Score: 6.3
VulDB Temp Score: 5.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Type confusion
CWE: CWE-843
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Timelineinfo

01/29/2019 🔍
03/14/2019 +44 days 🔍
03/19/2019 +5 days 🔍
04/26/2019 +38 days 🔍
04/27/2019 +1 days 🔍
11/26/2025 +2405 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: RHSA-2019:0966
Researcher: Markus Vervier (Nils)
Organization: X41 D-Sec GmbH
Status: Confirmed

CVE: CVE-2019-9791 (🔍)
GCVE (CVE): GCVE-0-2019-9791
GCVE (VulDB): GCVE-100-134156
SecurityFocus: 106773 - Mozilla Firefox MFSA2019-01 Multiple Security Vulnerabilities

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 04/27/2019 08:59
Updated: 11/26/2025 09:54
Changes: 04/27/2019 08:59 (63), 06/02/2020 21:03 (7), 09/07/2023 17:08 (4), 03/03/2025 08:59 (23), 11/26/2025 09:54 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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