CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Called exploited 97 days after disclosure.
Measured from the CVE publication date to the earliest of 3 KEV catalogues that list it.
The life of this vulnerability
- CVE published
- First KEV listing3mo
- Last sightingsame day
Gaps are compressed to equal steps. The elapsed time is printed under each.
Which catalogues call it exploited
- CISA KEVUS federallisted Sep 21, 2026
- EUVDENISA, European Unionlisted Sep 21, 2026
- VulnCheck KEVcommercial researchlisted Sep 21, 2026
- CIRCLaggregator, mirrors the abovelisted Sep 21, 2026, not counted
3 catalogues list it. CIRCL aggregates the others and is shown but not counted.
Public exploitation evidence
- reported exploitationwww.cisa.gov/sites/default/files/feeds/known_exploited_vulne
- reported exploitationwww.greynoise.io/blog/open-season-on-kapibala-attacker-steal
2 public reports collected from VulnCheck and CIRCL, first on Sep 21, 2026. Each links to its original source. We have not verified them.
Description
A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request.
Required action (CISA)
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
