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CVE-2026-74766— 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

Quick assessment

Affected
CVE-2026-74766
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

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. The XS backend inserts each decoded code point into the string buffer of the scalar it retu

EPSS 0.16% · P5

Affected Version Matrix 1

VendorProduct Version RangeStatus
None None 2.301< 2.590 affected

I. Basic Information for CVE-2026-74766

Vulnerability Information

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Vulnerability Title
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
Source: CVE Program / CVE List V5
Vulnerability Description
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. The XS backend inserts each decoded code point into the string buffer of the scalar it returns. decode_punycode computes the insertion pointer first and only then grows the buffer when the code point does not fit. The growth reallocates the buffer and updates every pointer except the insertion pointer, so the move that follows and the write of the code point go through a freed pointer. The buffer starts at twice the label length, and a code point above U+FFFF takes four bytes in the output, so a label of such code points outgrows it and forces the reallocation. Version 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected. Decoding an attacker-supplied punycode label reads and writes freed heap memory.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
- - 2.301 ~ 2.590 -

II. Public POCs for CVE-2026-74766

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III. Intelligence Information for CVE-2026-74766

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Patches & Fixes for CVE-2026-74766 (2)

Other References for CVE-2026-74766 (1)

Other References for CVE-2026-74766 (1)

IV. Related Vulnerabilities

Same weakness: CWE-416

V. Comments for CVE-2026-74766

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