CVE-2026-44659
CVE-2026-44659 is a medium-severity vulnerability with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-451.
Key facts
- Severity: Medium (CVSS 3.x base score 4.7)
- EPSS exploit prediction: 0% (6th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-29133
- Weakness: CWE-451
- Published:
- Last modified:
Description
Zen is a firefox-based browser. Prior to 1.19.12b, the ZEN Browser incorrectly truncates long hostnames in the address bar and shows only the attacker-controlled prefix of the subdomain, hiding the actual registrable domain (eTLD+1). As a result, an attacker can craft extremely long malicious subdomains that visually imitate trusted brands, and the browser will display only the spoofed prefix, misleading users about the actual origin of the site. This directly compromises the URL bar as a security indicator and creates a phishing/supply-chain attack vector. This vulnerability is fixed in 1.19.12b.
Frequently asked questions
- What is CVE-2026-44659?
- Zen is a firefox-based browser. Prior to 1.19.12b, the ZEN Browser incorrectly truncates long hostnames in the address bar and shows only the attacker-controlled prefix of the subdomain, hiding the actual registrable domain (eTLD+1). As a result, an attacker can craft extremely long malicious subdomains that visually imitate trusted brands, and the browser will display only the spoofed prefix, misleading users about the actual origin of the site. This directly compromises the URL bar as a security indicator and creates a phishing/supply-chain attack vector. This vulnerability is fixed in 1.19.12b.
- How severe is CVE-2026-44659?
- CVE-2026-44659 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2026-44659 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-44659?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-44659 have an EU (EUVD) identifier?
- Yes. CVE-2026-44659 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29133.
- When was CVE-2026-44659 published?
- CVE-2026-44659 was published on 2026-05-11 and last updated on 2026-06-17.
References
Other CWE-451 vulnerabilities
- CVE-2026-2634 — Critical (CVSS 9.8): Malicious scripts could cause desynchronization between the address bar and web content before a response is received…
- CVE-2026-0907 — Critical (CVSS 9.8): Incorrect security UI in Split View in Google Chrome prior to 144.0.7559.59 allowed a remote attacker to perform UI…
- CVE-2026-0906 — Critical (CVSS 9.8): Incorrect security UI in Google Chrome on Android prior to 144.0.7559.59 allowed a remote attacker to spoof the…
- CVE-2025-8043 — Critical (CVSS 9.8): Focus incorrectly truncated URLs towards the beginning instead of around the origin. This vulnerability was fixed in…
- CVE-2026-11175 — High (CVSS 8.8): Incorrect security UI in Messages in Google Chrome on Android prior to 149.0.7827.53 allowed a remote attacker to…
- CVE-2026-11172 — High (CVSS 8.8): Incorrect security UI in Contact Picker in Google Chrome on Android prior to 149.0.7827.53 allowed a remote attacker to…