Mozilla Firefox up to 148 Libraries denial of service

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.4$0-$5k0.00

Summaryinfo

A vulnerability was found in Mozilla Firefox up to 148. It has been classified as problematic. The impacted element is an unknown function of the component Libraries. This manipulation causes denial of service. This vulnerability is tracked as CVE-2026-4727. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 148 and classified as problematic. Affected by this vulnerability is an unknown code block of the component Libraries. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. The summary by CVE is:

Denial-of-service in the Libraries component in NSS. This vulnerability affects Firefox < 149 and Thunderbird < 149.

The advisory is shared at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-4727 since 03/24/2026. 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. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/28/2026). MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 304139 (Linux Distros Unpatched Vulnerability : CVE-2026-4727), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 149 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (304139). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.4

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

ADP CISA Base Score: 7.5
ADP CISA Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Denial of service
CWE: CWE-404
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: 304139
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-4727

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 149

Timelineinfo

03/24/2026 Advisory disclosed
03/24/2026 +0 days CVE reserved
03/24/2026 +0 days VulDB entry created
03/28/2026 +4 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-4727 (🔒)
GCVE (CVE): GCVE-0-2026-4727
GCVE (VulDB): GCVE-100-352777

Entryinfo

Created: 03/24/2026 14:46
Updated: 03/28/2026 20:13
Changes: 03/24/2026 14:46 (56), 03/28/2026 14:35 (2), 03/28/2026 20:13 (22)
Complete: 🔍
Cache ID: 216:06D:103

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