Mozilla Firefox up to 151 HTML type confusion

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.7$5k-$25k0.00

Summaryinfo

A vulnerability labeled as critical has been found in Mozilla Firefox up to 151. The impacted element is an unknown function of the component HTML Handler. Executing a manipulation can lead to Remote Code Execution. This vulnerability is registered as CVE-2026-12299. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 151 and classified as critical. This vulnerability affects an unknown part of the component HTML Handler. The manipulation with an unknown input leads to a remote code execution vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

The advisory is available at bugzilla.mozilla.org. This vulnerability was named CVE-2026-12299 since 06/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 07/09/2026).

The vulnerability scanner Nessus provides a plugin with the ID 321490 (Debian dsa-6350 : firefox-esr - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 152 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (321490) and CERT Bund (WID-SEC-2026-1959). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu 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: 5.9
VulDB Meta Temp Score: 5.7

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

ADP CISA Base Score: 5.4
ADP CISA Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Type confusion
CWE: CWE-843
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: 321490
Nessus Name: Debian dsa-6350 : firefox-esr - security update

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 152

Timelineinfo

06/15/2026 CVE reserved
06/16/2026 +1 days Advisory disclosed
06/16/2026 +0 days VulDB entry created
07/09/2026 +23 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-12299 (🔒)
GCVE (CVE): GCVE-0-2026-12299
GCVE (VulDB): GCVE-100-371290
CERT Bund: WID-SEC-2026-1959 - Mozilla Firefox, Firefox ESR und Thunderbird: Mehrere Schwachstellen

Entryinfo

Created: 06/16/2026 15:54
Updated: 07/09/2026 17:34
Changes: 06/16/2026 15:54 (54), 06/18/2026 14:14 (2), 06/20/2026 07:58 (7), 07/03/2026 03:53 (14), 07/09/2026 17:34 (1)
Complete: 🔍
Cache ID: 216::103

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

Discussion

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