# CVE-2026-121606: Qihoo 360 D621-2/D603-2/D600-2/D619/D606-6/D706 Firmware Signature Verification iscm verify_sign signature verification

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Qihoo 360 / D621-2: 6.4.0 (affected); 6.4.1 (affected); 6.4.2 (affected); 6.4.3 (affected); 6.4.4 (affected); 6.4.5 (affected); 6.4.6 (affected); 6.4.7 (affected); 6.4.8 (affected); 6.4.9 (affected). Source: CNA: VulDB
- Qihoo 360 / D603-2: 6.4.0 (affected); 6.4.1 (affected); 6.4.2 (affected); 6.4.3 (affected); 6.4.4 (affected); 6.4.5 (affected); 6.4.6 (affected); 6.4.7 (affected); 6.4.8 (affected); 6.4.9 (affected). Source: CNA: VulDB
- Qihoo 360 / D600-2: 6.4.0 (affected); 6.4.1 (affected); 6.4.2 (affected); 6.4.3 (affected); 6.4.4 (affected); 6.4.5 (affected); 6.4.6 (affected); 6.4.7 (affected); 6.4.8 (affected); 6.4.9 (affected). Source: CNA: VulDB
- Qihoo 360 / D619: 6.4.0 (affected); 6.4.1 (affected); 6.4.2 (affected); 6.4.3 (affected); 6.4.4 (affected); 6.4.5 (affected); 6.4.6 (affected); 6.4.7 (affected); 6.4.8 (affected); 6.4.9 (affected). Source: CNA: VulDB
- Qihoo 360 / D606-6: 6.4.0 (affected); 6.4.1 (affected); 6.4.2 (affected); 6.4.3 (affected); 6.4.4 (affected); 6.4.5 (affected); 6.4.6 (affected); 6.4.7 (affected); 6.4.8 (affected); 6.4.9 (affected). Source: CNA: VulDB
- Qihoo 360 / D706: 6.4.0 (affected); 6.4.1 (affected); 6.4.2 (affected); 6.4.3 (affected); 6.4.4 (affected); 6.4.5 (affected); 6.4.6 (affected); 6.4.7 (affected); 6.4.8 (affected); 6.4.9 (affected). Source: CNA: VulDB

## Severity and prioritization

- CVSS 4.0: 10 (critical); 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; source: CNA: VulDB

- CVSS 3.1: 10 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 3.0: 10 (critical); CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 2.0: 10 (critical); AV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:C; source: CNA: VulDB

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-347, CWE-345

## Exploit evidence

- exploit: https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 (CNA: VulDB)

## References

- https://vuldb.com/vuln/430443 (CNA: VulDB; vdb-entry, technical-description)

- https://vuldb.com/vuln/430443/cti (CNA: VulDB; signature, permissions-required)

- https://vuldb.com/cve/CVE-2026-121606 (CNA: VulDB; third-party-advisory)

- https://vuldb.com/submit/1023261 (CNA: VulDB; third-party-advisory)

- https://gist.github.com/gajgdm6-cpu/cf98af20ddb77f27a7c112214a6280f7 (CNA: VulDB; exploit)

## Provenance

- CNA: VulDB: https://www.cve.org/CVERecord?id=CVE-2026-121606; retrieved 2026-11-04; source updated 2026-11-04

Revision: 517d6da27d022ba0a0bdddb898930ee0213a3cce1bcfb9642775435be35d7b0f

Canonical: https://y2.dev/cve/CVE-2026-121606

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