CVE-2026-87079
UnknownSummary
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.
Risk Assessment
An attacker can supply a long label to exhaust CPU, causing denial of service in domain name processing applications.
Recommendation
Update Net::IDN::Punycode to version 2.590 or later. Consider limiting label length before decoding.
Other vulnerabilities in Net::IDN::Punycode
See all- CVE-2026-87082Unknown
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.
- 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 allow CPU exhaustion via quadratic insertion cost when decoding a long label in decode_punycode. The XS backend inserts each decoded code point into a UTF-8 buffer and finds the insertion point by scanning that buffer from the start, one character at a time. The scan runs once per code point over the output built so far, so the cost is quadratic in the label length. The pure-Perl backend downgrades its input to bytes so that substr can index it directly, but takes its working copy before the downgrade, so when the input carries the UTF-8 flag every substr on the copy scans from the start, with the same quadratic cost. Nothing bounds the label length in the to-Unicode direction. The 63-byte DNS limit is checked only when converting to ASCII, so domain_to_unicode and uts46_to_unicode pass an attacker-supplied label of any length to the decoder.