CVE-2026-87082
UnknownSummary
Net::IDN::Punycode versions before 2.590 for Perl do not validate UTF-8 input in encode_punycode. A flagged string with malformed bytes can hang, crash, or return a wrong label. Only direct calls to encode_punycode are affected; the decoder is not vulnerable.
Risk Assessment
An attacker can supply malicious bytes to cause a hang or crash in applications processing domain names, leading to denial of service or incorrect name resolution.
Recommendation
Update Net::IDN::Punycode to version 2.590 or later. Ensure input passed to encode_punycode is well-formed UTF-8.
Other vulnerabilities in Net::IDN::Punycode
See all- CVE-2026-87079Unknown
Net::IDN::Punycode versions before 2.590 for Perl allow CPU exhaustion via quadratic insertion cost when decoding long labels in decode_punycode. No label length limit exists in the to-Unicode direction, enabling CPU exhaustion attacks.
- CVE-2026-87078Unknown
Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode. No label length limit exists in the to-Unicode direction, allowing memory growth.
- CVE-2026-74766Unknown
Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode. Decoding an attacker-supplied punycode label reads and writes freed heap memory.
- CVE-2026-74765Unknown
Net::IDN::Punycode versions before 2.590 for Perl allow an out-of-bounds read via integer overflow of the delta accumulator in encode_punycode. Large code points can cause the digit index to leave the range of the digit table, leading to memory corruption or crash.
- CVE-2016-15059Unknown
Net::IDN::Punycode versions before 2.301 for Perl allow a heap buffer overflow via unchecked writes past the output buffer in encode_punycode. Some digit writes and the terminating NUL write do not check for room, leading to out-of-bounds writes.
Original NVD description (English source)
Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode. Neither backend checks that its input is well-formed UTF-8, so a string with the UTF-8 flag set over malformed bytes, as the :utf8 PerlIO layer produces from any malformed input, reaches the encoder unchecked. On perl 5.32 and later the XS backend reports a malformed sequence with a length of `(STRLEN)-1`, so the scan steps back one byte instead of forward and never ends. On earlier perls the XS returns a valid label for a different name. The pure-Perl backend runs a regex over the flagged string. Depending on the bytes, it aborts with SIGBUS on perl 5.28 and later, dies with a panic, or returns a wrong label. The documented conversion functions match the label against Unicode properties first and that match dies on such a string, so only a direct call to encode_punycode reaches the defect. The decoder is not affected. A direct caller encoding attacker-supplied bytes hangs, crashes or gets a label for a name the input never held.