CVE-2026-126349 (CVSS 3.1)

Description

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.0.0 until 2.9.1, Addressable::IDNA.to_unicode can decode Punycode labels that contain bidirectional controls, zero-width characters, control characters, or other default-ignorable format characters. Addressable::URI#display_uri can consequently show a reordered or visually indistinguishable hostname even though host, normalized_host, and network connections use the original encoded hostname. The pure-Ruby backend accepts the full prohibited set, while the native libidn backend is affected from 2.5.2 for characters added after Unicode 3.2. This issue is fixed in version 2.9.1.

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CVSS v3.1 Score

3.1

LOW

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

Weakness Type (CWE)

CWE-176 CWE-176

CWE-451 CWE-451

CWE-1007 CWE-1007

References

Other References

https://github.com/sporkmonger/addressable/commit/60455d32bb59fda2585a0e1865a9fcb21e8e55b1 https://github.com/sporkmonger/addressable/releases/tag/addressable-2.9.1 https://github.com/sporkmonger/addressable/security/advisories/GHSA-539f-xcgw-2gjg

Frequently Asked Questions

What is CVE-2026-126349? +

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.0.0 until 2.9.1, Addressable::IDNA.to_unicode can decode Punycode labels that contain bidirectional controls, zero-width characters, control characters, or other default-ignorable format characters. Addressable::URI#display_uri can consequently show a reordered or visually indistinguishable hostname even though host, normalized_host, and network connections use the original encoded hostname. The pure-Ruby backend accepts the full prohibited set, while the native libidn backend is affected from 2.5.2 for characters added after Unicode 3.2. This issue is fixed in version 2.9.1. It has a CVSS v3.1 base score of 3.1 (LOW).

How severe is CVE-2026-126349? +

CVE-2026-126349 has a CVSS v3.1 score of 3.1 out of 10, rated LOW. This is a low-severity vulnerability with limited impact.

How do I check if I'm vulnerable to CVE-2026-126349? +

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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