H3C Magic B1 Routers Exposed: Critical Buffer Overflow Publicly Exploitable
The National Vulnerability Database has disclosed CVE-2026-6581, a critical buffer overflow vulnerability in H3C Magic B1 routers, specifically affecting versions up to 100R004. This flaw resides within the SetMobileAPInfoById function of the /goform/aspForm file, where manipulating the param argument can trigger the overflow.
Rated with a CVSS score of 8.8 (HIGH), this vulnerability is remotely exploitable. The National Vulnerability Database confirms that a public exploit is now available, significantly escalating the risk for affected organizations. This means attackers don’t need to be on the local network to weaponize this flaw.
Despite early disclosure attempts, the vendor, H3C, has not responded. This lack of communication leaves defenders in a precarious position, with no official patch or workaround. The vulnerability’s public exploit availability demands immediate attention from any organization utilizing these specific H3C router models.
What This Means For You
- If your organization deploys H3C Magic B1 routers (versions up to 100R004), you are directly exposed to a high-severity, remotely exploitable buffer overflow. With a public exploit available and no vendor response, these devices are prime targets. Isolate or replace these devices immediately. Audit network logs for any suspicious activity originating from or targeting these routers.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
H3C Magic B1 SetMobileAPInfoById Buffer Overflow Attempt - CVE-2026-6581
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-6581 | Buffer Overflow | H3C Magic B1 up to 100R004 |
| CVE-2026-6581 | Buffer Overflow | Vulnerable function: SetMobileAPInfoById in /goform/aspForm |
| CVE-2026-6581 | Buffer Overflow | Vulnerable parameter: param |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 20, 2026 at 02:16 UTC |
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