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
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
9.8
Net::IDN::Punycode versions before 2.301 for Perl allow a heap buffer overflow via unchecked writes past the output buffer in encode_punycode
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.
- Record
CVE-2016-15059- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
EUVDEUVD-2016-10912
9.8
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.
- Record
EUVD-2016-10912- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6764-w6g6-m249
9.8
Net::IDN::Punycode versions before 2.301 for Perl allow a heap buffer overflow via unchecked...
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.
- Record
GHSA-6764-w6g6-m249- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
NVD
9.8
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.
- Record
CVE-2016-15059- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
OSV
9.8
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.
- Record
CVE-2016-15059- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2016-15059
9.8
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.
- Record
DEBIAN-CVE-2016-15059- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2016-15059
9.8
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.
- Record
UBUNTU-CVE-2016-15059- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libnet-idn-encode-perlDebian:12 |
before 2.303-1 | 2.303-1 |
libnet-idn-encode-perlDebian:13 |
before 2.303-1 | 2.303-1 |
libnet-idn-encode-perlDebian:14 |
before 2.303-1 | 2.303-1 |
libnet-idn-encode-perlUbuntu:16.04:LTS |
All versions, plus listed versions 2.202-12.300-12.300-1build1 |
None known |
libnet-idn-encode-perlUbuntu:18.04:LTS |
All versions, plus listed versions 2.400-1build1 |
None known |
libnet-idn-encode-perlUbuntu:20.04:LTS |
All versions, plus listed versions 2.500-12.500-1build1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2016-15059 is a critical vulnerability (CVSS 9.8) in libnet-idn-encode-perl, published September 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in libnet-idn-encode-perl 2.303-1.
References
rt.cpan.org/Ticket/Display.html?id=118924
github.com/robrwo/Net-IDN-Encode/commit/9a3ba07f15d22c0347eefee9625b012cbc803657.patch
metacpan.org/release/CFAERBER/Net-IDN-Encode-2.301/changes
openwall.com/lists/oss-security/2026/09/22/10
nvd.nist.gov/vuln/detail/CVE-2016-15059
github.com/advisories/GHSA-6764-w6g6-m249