CVE-2016-15059: Heap Overflow (CVSS 9.8)

Description

Net::IDN::Punycode versions before 2.301 for Perl allow a heap buffer overflow via unchecked writes past the output buffer in encode_punycode. The XS backend builds the encoded label in the string buffer of the scalar it returns, sized from the input length. The loop that emits the digits of each code point checks for room before every write, but the write of the last digit of each round and the write of the terminating NUL do not, so an input whose encoded form fills the buffer writes past its end. Only the XS backend is affected. Encoding an attacker-supplied string corrupts the heap.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0042

Probability of exploitation

0.35%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

References

Other References

https://github.com/robrwo/Net-IDN-Encode/commit/9a3ba07f15d22c0347eefee9625b012cbc803657.patch https://metacpan.org/release/CFAERBER/Net-IDN-Encode-2.301/changes https://rt.cpan.org/Ticket/Display.html?id=118924 http://www.openwall.com/lists/oss-security/2026/09/22/10

Frequently Asked Questions

What is CVE-2016-15059? +

Net::IDN::Punycode versions before 2.301 for Perl allow a heap buffer overflow via unchecked writes past the output buffer in encode_punycode. The XS backend builds the encoded label in the string buffer of the scalar it returns, sized from the input length. The loop that emits the digits of each code point checks for room before every write, but the write of the last digit of each round and the write of the terminating NUL do not, so an input whose encoded form fills the buffer writes past its end. Only the XS backend is affected. Encoding an attacker-supplied string corrupts the heap. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2016-15059? +

CVE-2016-15059 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0042, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2016-15059? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2016-15059