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CVE

CVE-2026-87078

Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode
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CVE

CVE-2026-87078

Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode

Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode.

The XS backend allocates the scalar it returns before it validates the input, sizing the buffer at twice the input length. The scalar is released only on the success path, so each of the three croaks that reject a label leaves the scalar and its buffer allocated. Nothing bounds the label length in the to-Unicode direction, since the 63-byte DNS limit is checked only when converting to ASCII.

Only the XS backend is affected.

A sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.1
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
C
H
U
-

Related Resources

No items found.

References

http://www.openwall.com/lists/oss-security/2026/09/22/13, https://cpan.org/modules, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87078.json, https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes, https://nvd.nist.gov/vuln/detail/CVE-2026-87078, https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch, https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch, https://github.com/robrwo/Net-IDN-Encode

Severity

9.1

CVSS Score
0
10

Basic Information

Base CVSS
9.1
EPSS Probability
0.00394%
EPSS Percentile
0.32102%
Introduced Version
0
Fix Available
6b903cf0aeb82ff60e98e180a26daf3f9943f167,0:2.590-1.amzn2023.0.1

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