What’s Vulnerable › Vulnerabilities

CVE-2023-4578: Error reporting methods in SpiderMonkey could have triggered an Out of Memory Exception

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-09-11 · updated 2026-06-17
• Weakness: CWE-770

Description

When calling `JS::CheckRegExpSyntax` a Syntax Error could have been set which would end in calling `convertToRuntimeErrorAndClear`. A path in the function could attempt to allocate memory when none is available which would have caused a newly created Out of Memory exception to be mishandled as a Syntax Error. This vulnerability affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

Affected products

• Mozilla Firefox: before 117.0 — fixed in 117.0
• Mozilla Firefox ESR: before 115.2 — fixed in 115.2
• Mozilla Thunderbird: before 115.2 — fixed in 115.2

How to fix

Upgrade to a fixed version: Mozilla Firefox 117.0; Mozilla Firefox ESR 115.2; Mozilla Thunderbird 115.2. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1839007
• https://www.mozilla.org/security/advisories/mfsa2023-34/
• https://www.mozilla.org/security/advisories/mfsa2023-36/
• https://www.mozilla.org/security/advisories/mfsa2023-38/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1839007
• https://www.mozilla.org/security/advisories/mfsa2023-34/
• https://www.mozilla.org/security/advisories/mfsa2023-36/
• https://www.mozilla.org/security/advisories/mfsa2023-38/

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