VulnerabilityPublished 13 Nov 2026

CVE-2026-126348: Uffizzi · Addressable display_uri can show misleading hosts with invalid Punycode A-labels

Affects uffizziSource GCVE Database

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Authoritative record:CVE-2026-126348· Medium 4.3

Not known to be exploited · CVSS 4.3 Medium · fixed in 2.9.1 : update uffizzi when convenient.

Data as of 13 Nov 2026, 21:05 UTC

CVSS 3.1 base score

4.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	4.3

Patch: Available – fixed in 2.9.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Homebrewuffizzi`pkg:brew/uffizzi`Other threats	Affected >=2.3.4	Fixed in–

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AI-suggested

A fix is available in Addressable version 2.9.1, which returns invalid Punycode labels unchanged in to_unicode, aligning behavior with the native IDNA implementation. Users should upgrade to version 2.9.1 or later. Alternatively, installing libidn and the idn-ruby gem forces Addressable to use the native IDNA implementation, which is not vulnerable. Applications should avoid making security decisions based on display_uri or to_unicode output and instead use normalized_host for hostname comparisons.

Description

A vulnerability in the Addressable Ruby library's pure-Ruby IDNA implementation allows certain invalid Punycode A-labels to be decoded incorrectly by the to_unicode method. This causes display_uri to show misleading hostnames that differ from the actual host used in connections, potentially enabling attackers controlling a domain to impersonate other hosts in displayed URIs. The issue affects Addressable versions 2.0.0 and later when using the pure-Ruby implementation and is fixed in version 2.9.1. The native IDNA implementation is not affected.

Impact

This vulnerability can cause applications to display misleading hostnames for URLs containing invalid Punycode labels, potentially enabling phishing or spoofing attacks by making a malicious domain appear as a trusted one in user interfaces or security checks that rely on to_unicode or display_uri output. However, actual network connections use the correct host, so the impact is limited to display and hostname comparison logic. There is no direct compromise of confidentiality or availability.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Nov 2026, 21:05 UTC

Technical details

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