Mozilla Firefox/Firefox ESR/Thunderbird SMIL Animation Controller use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability was found in Mozilla Firefox, Firefox ESR and Thunderbird (Web Browser) (version now known). It has been declared as critical. Affected by this vulnerability is some unknown processing of the component SMIL Animation Controller. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability.

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 at This vulnerability is known as CVE-2019-9796 since 03/14/2019. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available.

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.

Entries connected to this vulnerability are available at 130538, 134153, 134155 and 134156.






CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.9

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

NVD Base Score: 9.8
NVD Vector: 🔍



VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍


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

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

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EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍


01/29/2019 🔍
03/14/2019 +44 days 🔍
03/19/2019 +5 days 🔍
04/26/2019 +38 days 🔍
04/27/2019 +1 days 🔍
09/07/2023 +1594 days 🔍



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

CVE: CVE-2019-9796 (🔍)
SecurityFocus: 106773 - Mozilla Firefox MFSA2019-01 Multiple Security Vulnerabilities

See also: 🔍


Created: 04/27/2019 09:05 AM
Updated: 09/07/2023 05:46 PM
Changes: 04/27/2019 09:05 AM (61), 06/03/2020 06:55 AM (7), 09/07/2023 05:46 PM (4)
Complete: 🔍


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