Zyxel GS1900-24E firmware: a memory flaw attackers can abuse
WHAT IT IS · ROUTERS, CAMERAS AND DEVICESRouters, cameras and recorders are often forgotten and rarely updated.
DO THIS FIRSTUpdate it or replace it. Never leave its admin page open to the internet. Not sure if you use it? Send this page to your IT provider or security lead and ask.
TECHNICAL SUMMARY An out-of-bounds write vulnerability in the CGI program of Zyxel GS1900-24E firmware versions through 2.90(AAHK.2)C0 could allow an unauthenticated adjacent attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request.
WHY THIS VERDICT One source reports attacks and the vulnerability is 8 days old. In our backtest a single early report was confirmed within 30 days about one time in twenty, so we wait for a second report or for attack attempts to be seen.
WHY IT RANKS HERE Exploitation is reported. The first report is 3 days old. 10 products are affected.
- HIGHEST CONFIRMED RUNG
- TALK
- CISA KEV
- NOT YET
- EXPLOIT CODE
- NONE KNOWN
How far has it climbed?
01 TALK
■ CONFIRMEDNEWEST EVIDENCE · 3 INDEPENDENT SOURCESCVE-2026-107441 discussed publicly (CIRCL sighting). Zyxel Switch Hacks Blamed on Patched Flaw Actually Exploited a Zero-Day.
02 EXPOSED
□ NOT TRACKED YETNO SOURCE FOR THIS STEP YETWe have no source that counts exposed systems yet. Internet scan data needs a partnership we do not have. No evidence here does not mean nothing is exposed.
03 TRIED
▨ REPORTED, NOT CONFIRMEDNEWEST EVIDENCE · 1 SOURCEAttacks that worked are reported (step 4), so attempts count as reported too.
04 EXPLOITED
▨ REPORTED, NOT CONFIRMEDNEWEST EVIDENCE · 1 SOURCEExploitation of CVE-2026-107441 reported (CIRCL sighting).
05 DAMAGE
□ NOT TRACKED YETNO SOURCE FOR THIS STEP YETBreach notices and filings rarely name the flaw that was used, so we cannot link them to this event yet. No evidence here does not mean no harm.
When each thing happened
- DISCLOSED
- EXPLOIT CODE PUBLICNOT YET
- FIRST ATTACK REPORT
- CISA KEV LISTINGNOT YET
- US FEDERAL DEADLINENOT YET
Questions to ask this week
- Do we run Zyxel GS1900-24E firmware? If yes, is it patched or cut off from the internet?
- Who owns fixing it, and by what date?
- Have we checked for signs of attack since the first report, not just since the patch?
How it unfolded
- NOV 4, 2026Zyxel security advisory (AV26-1114) – Update 1
- NOV 5, 2026Zyxel Switch Hacks Blamed on Patched Flaw Actually Exploited a Zero-Day
- Attack activity. NOV 8, 2026Exploitation of CVE-2026-107441 reported (CIRCL sighting)
- NOV 9, 2026CVE-2026-107441 discussed publicly (CIRCL sighting)
SOURCES
- [1] CIRCL Vulnerability-Lookup sightings: CVE-2026-107441 discussed publicly (CIRCL sighting), NOV 9
- [2] CIRCL Vulnerability-Lookup sightings: Exploitation of CVE-2026-107441 reported (CIRCL sighting), NOV 8
- [3] SecurityWeek: Zyxel Switch Hacks Blamed on Patched Flaw Actually Exploited a Zero-Day, NOV 5
- [4] Canadian Centre for Cyber Security: Zyxel security advisory (AV26-1114) – Update 1, NOV 4