What’s Vulnerable › Vulnerabilities

CVE-2026-115897: Serialize JavaScript: Cross-site scripting (XSS) via unescaped </script at the end of a serialized function body

• Severity: low (CVSS 2.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-23 · updated 2026-10-26
• Weakness: CWE-79

Description

Serialize JavaScript serializes JavaScript values to a superset of JSON that includes regular expressions and functions. Prior to 7.1.3, the function-source escaping logic does not neutralize a bare closing-script prefix when attacker-influenced function source text ends exactly at that prefix. Because each function body is escaped independently, a delimiter supplied by surrounding serialized output can terminate an HTML script element, and a later serialized value supplies injected markup that becomes a live element in the page. Exploitation requires control of a serialized function's source text, such as through a spoofed toString(). This issue is fixed in version 7.1.3.

Affected products

• yahoo serialize-javascript: before 7.1.3

References

• https://github.com/yahoo/serialize-javascript/commit/2864b3c6260a3bfd52d2db3e70d1a079de108a61
• https://github.com/yahoo/serialize-javascript/pull/235
• https://github.com/yahoo/serialize-javascript/releases/tag/v7.1.3
• https://github.com/yahoo/serialize-javascript/security/advisories/GHSA-m5mm-p8h7-m29v

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