Is CVE-2026-8764 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-8764 being exploited in the wild.

How severe is CVE-2026-8764?

High severity, with a CVSS score of 7.2, published 17 May 2026.

Is there a fix for CVE-2026-8764?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-8764 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-8764?

Check whether you run H3C Magic B3 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-8764: H3C Magic B3 buffer overflow in UpdateWanParams

CVE-2026-8764 · Severity: high · CVSS 7.2 · Published 2026-05-17

A security vulnerability exists in the H3C Magic B3 router, a device used to provide internet connectivity and network management. An attacker with administrative access can send a specially crafted request to the router's management interface to cause a system crash or potentially take full control of the device. This could lead to a total loss of internet service for the connected network or unauthorized access to network traffic.

Vendors: H3C.

Quick answers

Is CVE-2026-8764 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-8764 being exploited in the wild.
How severe is CVE-2026-8764?: High severity, with a CVSS score of 7.2, published 17 May 2026.
Which products and versions are affected?: H3C Magic B3 up to 100R002.
Is there a fix for CVE-2026-8764?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-8764 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-8764?: Check whether you run H3C Magic B3 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A stack-based buffer overflow vulnerability exists in the H3C Magic B3 router (firmware up to 100R002) within the 'UpdateWanParams' function of the '/goform/aspForm' interface. The root cause is an inconsistency between input validation and memory allocation: while the 'param' argument is restricted to 512 bytes, the subsequent copy operation targets a destination buffer of only 64 bytes without further bounds checking. An attacker with high privileges (authenticated administrator) can exploit this via a crafted POST request to overwrite adjacent memory. This can result in a crash of the web management service, a device reboot (DoS), or potentially remote code execution (RCE). As of the advisory date, the vendor has not responded to disclosure efforts, and no official patch is available.

Affected products

H3C Magic B3 up to 100R002

Timeline

2026-04-23: disclosed: Vulnerability details and PoC published on GitHub
2026-05-17: advisory: CVE-2026-8764 published by VulDB/NVD

References

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