Is CVE-2023-23603 in the CISA KEV catalog?

No. CVE-2023-23603 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2023-23603?

CVE-2023-23603 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2023-23603?

CVE-2023-23603 has an EPSS score of 0.64% (46th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2023-23603?

Upgrade firefox on debian unstable to 109.0-1 or later. Fixes are available for 7 affected products.

CVE & CISA-KEV Catalog

CVE-2023-23603

MEDIUM

6.5

CVSS v3

NVD

Description

Regular expressions used to filter out forbidden properties and values from style directives in calls to `console.log` weren't accounting for external URLs. Data could then be potentially exfiltrated from the browser. This vulnerability affects Firefox < 109, Firefox ESR < 102.7, and Thunderbird < 102.7.

CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

firefoxDebian

Fixed in:109.0-1CVE-2023-23603

firefoxUbuntu

Fixed in:109.0+build2-0ubuntu0.18.04.1USN-5816-1

Fixed in:109.0+build2-0ubuntu0.20.04.1USN-5816-1

thunderbirdUbuntu

Fixed in:1:102.7.1+build2-0ubuntu0.18.04.1USN-5824-1

Fixed in:1:102.7.1+build2-0ubuntu0.20.04.1USN-5824-1

Fixed in:1:102.7.1+build2-0ubuntu0.22.04.1USN-5824-1

Fixed in:1:102.7.1+build2-0ubuntu0.22.10.1USN-5824-1

DeveloperEditionWindows application

Affected:109.0Fixed in:109.0Mozilla

Mozilla Firefox (en-US)Windows application

Affected:109.0Fixed in:109.0Mozilla

Mozilla Firefox ESR (en-US)Windows application

Affected:102.7Fixed in:102.7Mozilla

Mozilla Thunderbird (en-US)Windows application

Affected:102.7Fixed in:102.7Mozilla

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Exploit Intelligence

0.64%probability of exploitation in 30 days

46thpercentile

Moderate risk: more likely to be exploited than 46% of all known CVEs.

References

Vendor Advisory4

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-50387	High	7.5	100%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-27316	High	7.5	91%	-	Fix
CVE-2022-30522	High	7.5	90%	-	Fix
CVE-2019-9515	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-12-18.