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GHSA-29x4-r6jv-ff4w

MediumCVSS 6.5 / 10
Published Apr 18, 2026·Last modified May 12, 2026
Affected Components(0)

No affected components available

Description

A vulnerability in Zebra's JSON-RPC HTTP middleware allows an authenticated RPC client to cause a Zebra node to crash by disconnecting before the request body is fully received. The node treats the failure to read the HTTP request body as an unrecoverable error and aborts the process instead of returning an error response.

Severity

Moderate - This is a Denial of Service (DoS) that requires a client capable of passing Zebra's cookie authentication, which is enabled by default.

Affected Versions

  • zebrad: versions from 2.2.0 up to (but not including) 4.3.1
  • zebra-rpc: versions from 1.0.0-beta.45 up to (but not including) 6.0.2

Description

Zebra's JSON-RPC HTTP middleware treated a failure to read the incoming HTTP request body as an unrecoverable error, aborting the process rather than returning an error response. A client that disconnected after sending only part of a request body, for example, by resetting the TCP connection mid-transfer, was sufficient to trigger the crash. The vulnerability could be exploited only by authenticated RPC clients. Nodes running the shipped defaults, with RPC bound to localhost and cookie authentication on, were not vulnerable.

Impact

Denial of Service

  • Attack Vector: Network, authenticated (requires a valid RPC cookie when cookie authentication is enabled).
  • Effect: Immediate crash of the Zebra node.
  • Scope: Any node whose RPC interface is reachable by a client with valid credentials, or any node with cookie authentication disabled and an exposed RPC interface.

Fixed Versions

This issue is fixed in Zebra 4.3.1 (crate zebra-rpc 6.0.2).

The fix propagates failures to read the HTTP request body as ordinary error responses, so Zebra now rejects truncated or interrupted requests rather than crashing.

Mitigation

Users should upgrade to Zebra 4.3.1 or later.

If an immediate upgrade is not possible, users should ensure their RPC port is not exposed to untrusted networks and that cookie authentication remains enabled (the default).

References

Credits

Thanks to shieldedonly who discovered this issue and reported it via our coordinated disclosure process.

Risk Scores
Base Score
6.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.

Threat Intelligence
6.0

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.26%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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