VulnerabilityPublished 12 Nov 2026

CVE-2026-126349: Addressable display_uri can show misleading hosts containing bidi and invisible characters

Affects addressableSource GCVE Database

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Authoritative record:CVE-2026-126349· Low 3.1

Not known to be exploited · CVSS 3.1 Low : upgrade to 2.9.1 when convenient.

Data as of 12 Nov 2026, 23:20 UTC

CVSS 3.1 base score

3.1Low

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	3.1

Patch: Available – fixed in 2.9.1

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

Attack Vector: Network
Attack Complexity: High
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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 12 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

Upgrade addressable to 2.9.1.

Affected software

Product	Affected	Fixed in
RubyGemsaddressable	Affected >=2.0.0 <2.9.1	Fixed in 2.9.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Addressable version 2.9.1, which should be applied to prevent misleading host displays. As a workaround, installing libidn and the idn-ruby gem enables the native IDNA implementation, reducing the affected characters. Additionally, applications can detect bidirectional and invisible characters in displayed hosts and fallback to using normalized_host instead of display_uri when such characters are present.

Description

Addressable library versions from 2.0.0 up to but not including 2.9.1 have a vulnerability in the display_uri method where Unicode bidirectional and invisible characters in Punycode-encoded hostnames can cause misleading visual representations. This can make malicious domains appear as trusted ones in user interfaces that show display_uri, such as link previews or email clients. The underlying host parsing and connections are unaffected. The issue is fixed in version 2.9.1.

Impact

This vulnerability can be exploited to visually spoof domain names in user interfaces that display the URI using display_uri, potentially tricking users into trusting malicious domains. There is no impact on URI parsing or network connections, so the risk is limited to user deception via misleading host display. The CVSS score is low (3.1) reflecting the requirement for user interaction and the complexity of exploitation.

Summary

The Addressable Ruby library's IDNA.to_unicode method decodes Punycode labels containing bidirectional control characters (e.g., U+202E RIGHT-TO-LEFT OVERRIDE) and invisible format characters, which can reorder or visually alter the displayed hostname in display_uri. This allows an attacker to craft domain names that appear visually similar or identical to trusted domains, potentially misleading users. The pure-Ruby IDNA implementation (Addressable >= 2.0.0) decodes all such characters, including those disallowed by IDNA nameprep. The native IDNA implementation (Addressable >= 2.5.2) rejects most but not all problematic characters, especially those added after Unicode 3.2. The vulnerability is resolved in Addressable 2.9.1 by returning such labels unchanged, preventing misleading display. Parsing and network connections remain unaffected; only the visual display is impacted.

CWE-1007Insufficient Visual Distinction of Homoglyphs Presented to User (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product displays information or identifiers to a user, but the display mechanism does not make it easy for the user to distinguish between visually similar or identical glyphs (homoglyphs), which may cause the user to misinterpret a glyph and perform an unintended, insecure action.
Implementation
Use a browser that displays Punycode for IDNs in the URL and status bars, or which color code various scripts in URLs.
Implementation
Use an email client that has strict filters and prevents messages that mix character sets to end up in a user's inbox.
Attack patterns
Homograph Attack via Homoglyphs (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-176Improper Handling of Unicode Encoding (opens in a new tab)
Variant weakness
The product does not properly handle when an input contains Unicode encoding.
Architecture and Design · Input Validation
Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Unvalidated Redirects and Forwards (opens in a new tab)
XML Security (opens in a new tab)
XML External Entity Prevention (opens in a new tab)
File Upload (opens in a new tab)
Input Validation (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.2 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
Using Unicode Encoding to Bypass Validation Logic (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-451User Interface (UI) Misrepresentation of Critical Information (opens in a new tab)
Class weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The user interface (UI) does not properly represent critical information to the user, allowing the information - or its source - to be obscured or spoofed. This is often a component in phishing attacks.
Implementation · Input Validation
Perform data validation (e.g. syntax, length, etc.) before interpreting the data.
Architecture and Design · Output Encoding
Create a strategy for presenting information, and plan for how to display unusual characters.
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
Attack patterns
Spear Phishing (opens in a new tab)
Mobile Phishing (opens in a new tab)
Phishing (opens in a new tab)
Resource Location Spoofing (opens in a new tab)
Action Spoofing (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Nov 2026, 23:20 UTC

WeaknessesCWE-1007, CWE-176, CWE-451

Technical details

References

Community reviews

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