Mozilla Firefox up to 147 WebRender sandbox

CVSS Meta Temp Score
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CTI Interest Score
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8.7$5k-$25k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Mozilla Firefox up to 147. The affected element is an unknown function of the component WebRender. This manipulation causes sandbox. This vulnerability is handled as CVE-2026-2761. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mozilla Firefox up to 147. It has been declared as critical. Affected by this vulnerability is an unknown functionality of the component WebRender. The manipulation with an unknown input leads to a sandbox vulnerability. The CWE definition for the vulnerability is CWE-265. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Sandbox escape in the Graphics: WebRender component. This vulnerability affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

It is possible to read the advisory at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-2761 since 02/19/2026. The exploitation appears to be easy. 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. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 03/03/2026). The attack technique deployed by this issue is T1611 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 299964 (RHEL 10 : firefox (RHSA-2026:3361)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 148 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (299964) and CERT Bund (WID-SEC-2026-0497). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Debian Linux
  • Red Hat Enterprise Linux
  • SUSE Linux
  • Oracle Linux
  • IGEL OS
  • SUSE openSUSE
  • RESF Rocky Linux
  • Mozilla Firefox
  • Mozilla Firefox ESR
  • Mozilla Thunderbird

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.7

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

NVD Base Score: 10.0
NVD Vector: 🔒

ADP CISA Base Score: 10.0
ADP CISA Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Sandbox
CWE: CWE-265 / CWE-264
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: 299964
Nessus Name: RHEL 10 : firefox (RHSA-2026:3361)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 148

Timelineinfo

02/19/2026 CVE reserved
02/24/2026 +5 days Advisory disclosed
02/24/2026 +0 days VulDB entry created
03/03/2026 +7 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-2761 (🔒)
GCVE (CVE): GCVE-0-2026-2761
GCVE (VulDB): GCVE-100-347551
CERT Bund: WID-SEC-2026-0497 - Mozilla Firefox, Firefox ESR und Thunderbird: Mehrere Schwachstellen

Entryinfo

Created: 02/24/2026 16:04
Updated: 03/03/2026 13:50
Changes: 02/24/2026 16:04 (56), 02/26/2026 05:24 (2), 02/28/2026 10:33 (21), 03/02/2026 11:38 (7), 03/03/2026 13:50 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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