Mozilla Firefox up to 149 Web Codecs uninitialized pointer

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.9$5k-$25k0.00

Summaryinfo

A vulnerability has been found in Mozilla Firefox up to 149 and classified as critical. Affected is an unknown function of the component Web Codecs. The manipulation leads to uninitialized pointer. This vulnerability is referenced as CVE-2026-6748. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Mozilla Firefox up to 149. This issue affects an unknown part of the component Web Codecs. The manipulation with an unknown input leads to a uninitialized pointer vulnerability. Using CWE to declare the problem leads to CWE-824. The product accesses or uses a pointer that has not been initialized. The impact remains unknown. The summary by CVE is:

Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

The advisory is shared at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2026-6748 since 04/21/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/02/2026).

The vulnerability scanner Nessus provides a plugin with the ID 309101 (Mozilla Thunderbird < 140.10), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 150 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (309101) and CERT Bund (WID-SEC-2026-1228). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

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

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

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: 🔍

ADP CISA Base Score: 9.8
ADP CISA Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Uninitialized pointer
CWE: CWE-824 / CWE-908
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: 309101
Nessus Name: Mozilla Thunderbird < 140.10

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 150

Timelineinfo

04/21/2026 Advisory disclosed
04/21/2026 +0 days CVE reserved
04/21/2026 +0 days VulDB entry created
07/02/2026 +72 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-6748 (🔒)
GCVE (CVE): GCVE-0-2026-6748
GCVE (VulDB): GCVE-100-358445
CERT Bund: WID-SEC-2026-1228 - Mozilla Thunderbird, Firefox ESR und Firefox: Mehrere Schwachstellen

Entryinfo

Created: 04/21/2026 15:55
Updated: 07/02/2026 08:42
Changes: 04/21/2026 15:55 (55), 04/22/2026 16:20 (2), 05/15/2026 11:34 (7), 07/02/2026 08:42 (12)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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