VDB-380887 · CVE-2026-16381 · GCVE-0-2026-16381

Mozilla Firefox DNS cross-domain policy

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.1	$5k-$25k	0.55

Summaryinfo

A vulnerability has been found in Mozilla Firefox and classified as problematic. Affected by this issue is some unknown functionality of the component DNS. This manipulation causes cross-domain policy. This vulnerability is tracked as CVE-2026-16381. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Mozilla Firefox (the affected version unknown). It has been declared as problematic. Affected by this vulnerability is an unknown part of the component DNS. The manipulation with an unknown input leads to a cross-domain policy vulnerability. The CWE definition for the vulnerability is CWE-942. The product uses a cross-domain policy file that includes domains that should not be trusted. As an impact it is known to affect confidentiality. The summary by CVE is:

Same-origin policy bypass in the Networking: DNS component. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13.

It is possible to read the advisory at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-16381 since 07/20/2026. The exploitation appears to be difficult. 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 07/21/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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

Productinfo

Type

Web Browser

Vendor

Mozilla

Name

Firefox

License

open-source

Website

Vendor: https://www.mozilla.org/
Product: https://www.mozilla.org/en-US/firefox/

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.1
VulDB Meta Temp Score: 3.1

VulDB Base Score: 3.1
VulDB Temp Score: 3.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Cross-domain policy
CWE: CWE-942 / CWE-346 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/20/2026 CVE reserved
07/21/2026 +1 days Advisory disclosed
07/21/2026 +0 days VulDB entry created
07/21/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-16381 (🔒)
GCVE (CVE): GCVE-0-2026-16381
GCVE (VulDB): GCVE-100-380887

Entryinfo

Created: 07/21/2026 15:47
Changes: 07/21/2026 15:47 (52)
Complete: 🔍
Cache ID: 216::103