CVE-2026-87081
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
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
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
CVE-2026-87081- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-407
- Updated
- 2026-11-02
EUVDEUVD-2026-84294
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
EUVD-2026-84294- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-653x-rhrr-h9h8
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode...
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
GHSA-653x-rhrr-h9h8- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-407
- Updated
- 2026-11-02
NVD
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
CVE-2026-87081- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-407
- Updated
- 2026-11-02
OSV
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
CVE-2026-87081- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-407
- Updated
- 2026-11-07
OSVDEBIAN-CVE-2026-87081
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii. to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
DEBIAN-CVE-2026-87081- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
OSVUBUNTU-CVE-2026-87081
7.5
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii. to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
- Record
UBUNTU-CVE-2026-87081- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:12468-1 No score
perl-Net-IDN-Encode-2.600.0-1.1 on GA media
These are all security issues fixed in the perl-Net-IDN-Encode-2.600.0-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:12468-1- Updated
- 2026-11-07
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libnet-idn-encode-perlDebian:12 |
All versions, plus listed versions 2.500-32.500-52.502-12.600-1 |
None known |
libnet-idn-encode-perlDebian:13 |
All versions, plus listed versions 2.500-52.502-12.600-1 |
None known |
libnet-idn-encode-perlDebian:14 |
before 2.600-1, plus listed versions 2.500-52.502-1 |
2.600-1 |
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 |
libnet-idn-encode-perlUbuntu:22.04:LTS |
All versions, plus listed versions 2.500-1build22.500-22.500-2build1 |
None known |
libnet-idn-encode-perlUbuntu:24.04:LTS |
All versions, plus listed versions 2.500-32.500-3build12.500-3build22.500-5 |
None known |
libnet-idn-encode-perlUbuntu:26.10 |
All versions, plus listed versions 2.500-5build12.500-5build2 |
None known |
libnet-idn-encode-perlUbuntu:26.04:LTS |
All versions, plus listed versions 2.500-5build1 |
None known |
perl-Net-IDN-EncodeopenSUSE:Tumbleweed From an advisory covering 7 CVEs |
before 2.600.0-1.1 | 2.600.0-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, references | OSV | |
| facts | OSV | |
| affected, facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-87081 is a high vulnerability (CVSS 7.5) 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 0.38%, the 32nd percentile. Fixed in libnet-idn-encode-perl 2.600-1.
References
metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes
github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch
github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch
openwall.com/lists/oss-security/2026/09/22/16
nvd.nist.gov/vuln/detail/CVE-2026-87081
github.com/advisories/GHSA-653x-rhrr-h9h8
Show 14 moreShow less
cpan.org/modules
github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87081.json
github.com/robrwo/Net-IDN-Encode
security-tracker.debian.org/tracker/CVE-2026-87081
ubuntu.com/security/CVE-2026-87081
cve.org/CVERecord?id=CVE-2026-87081
lists.security.metacpan.org/cve-announce/msg/43753018
suse.com/security/cve/CVE-2026-74765
suse.com/security/cve/CVE-2026-74766
suse.com/security/cve/CVE-2026-87078
suse.com/security/cve/CVE-2026-87079
suse.com/security/cve/CVE-2026-87080
suse.com/security/cve/CVE-2026-87081
suse.com/security/cve/CVE-2026-87082