Mozilla Firefox up to 108 WebSocket cross-domain policy

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.3$5k-$25k0.00

Summaryinfo

A vulnerability has been found in Mozilla Firefox up to 108 and classified as critical. This vulnerability affects unknown code of the component WebSocket Handler. Performing a manipulation results in cross-domain policy. This vulnerability is identified as CVE-2023-23602. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in Mozilla Firefox up to 108 (Web Browser). This affects an unknown part of the component WebSocket Handler. The manipulation with an unknown input leads to a cross-domain policy vulnerability. CWE is classifying the issue as CWE-942. The product uses a cross-domain policy file that includes domains that should not be trusted. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A mishandled security check when creating a WebSocket in a WebWorker caused the Content Security Policy connect-src header to be ignored. This could lead to connections to restricted origins from inside WebWorkers. This vulnerability affects Firefox < 109, Firefox ESR < 102.7, and Thunderbird < 102.7.

The weakness was released 01/17/2023 by Dave Vandyke as Bug 1800890 as confirmed advisory (Website). It is possible to read the advisory at bugzilla.mozilla.org. The advisory contains:

A mishandled security check when creating a WebSocket in a WebWorker caused the Content Security Policy connect-src header to be ignored. This could lead to connections to restricted origins from inside WebWorkers.
This vulnerability is uniquely identified as CVE-2023-23602. 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 12/18/2025).

Upgrading to version 109 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-27702). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

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

NVD Base Score: 6.5
NVD Vector: 🔍

CNA Base Score: 6.5
CNA Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: Firefox 109

Timelineinfo

01/16/2023 🔍
01/17/2023 +1 days 🔍
01/17/2023 +0 days 🔍
01/19/2023 +2 days 🔍
12/18/2025 +1064 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: Bug 1800890
Researcher: Dave Vandyke
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2023-23602 (🔍)
GCVE (CVE): GCVE-0-2023-23602
GCVE (VulDB): GCVE-100-218991
EUVD: 🔍

Entryinfo

Created: 01/19/2023 14:20
Updated: 12/18/2025 20:58
Changes: 01/19/2023 14:20 (13), 01/19/2023 14:21 (4), 01/19/2023 14:24 (29), 02/15/2023 13:09 (1), 01/10/2025 21:38 (36), 04/28/2025 04:43 (3), 10/14/2025 05:21 (1), 12/18/2025 20:58 (1)
Complete: 🔍
Cache ID: 216::103

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

Discussion

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