CyberRota Analysis
AI-GeneratedVersions of the URI library prior to 5.36 for Perl are vulnerable due to a lack of proper Unicode normalization in the nameprep process, which can lead to discrepancies between encoded host labels and their normalized forms. This vulnerability can result in security decisions based on untrusted input being bypassed, as checks may yield different results than actual resolutions, potentially allowing unauthorized access or exploitation. Organizations using this library for security-sensitive applications, such as allow/deny lists or SSRF filters, should prioritize addressing this issue to mitigate risks.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
Note: these links are listed for security research and verification purposes only.
Original NVD Description
URI versions before 5.36 for Perl encode non-NFC host names to non-standard punycode labels via missing normalization in nameprep. nameprep lowercases each host label but performs no Unicode normalization. IDNA requires a label to be normalized to Form C before it is encoded (RFC 5891), so a label that is not already in NFC is encoded to a different A-label than its normalized form. A label built from the precomposed Devanagari sequence U+0958 U+093E encodes to xn--72b5c without normalization but to xn--11b2fg after NFC normalization, and xn--72b5c does not round-trip back to the original label. Any caller that reads host() from a URI built from untrusted input and uses it for a security decision (an allow or deny list, an SSRF filter, deduplication, a cache key) sees the non-standard label, while a client that fetches the same URL resolves the NFC form, so the check and the fetch can disagree about the host.