Is CVE-2026-52130 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-52130 being exploited in the wild.

How severe is CVE-2026-52130?

High severity, with a CVSS score of 7.5, published 1 September 2026.

Which products and versions are affected?

ggml-org llama.cpp b5693 and earlier.

Is there a fix for CVE-2026-52130?

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-2026-52130 attacked?

It is attacked over the network.

Am I affected by CVE-2026-52130?

Check whether you run GGML Llama.Cpp. 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-2026-52130: llama.cpp uncontrolled recursion in JSON schema converter

CVE-2026-52130 · Severity: high · CVSS 7.5 · Published 2026-09-01

llama.cpp is an open-source framework for running large language models locally. The framework contains a denial-of-service vulnerability in its JSON schema parsing logic that can crash the server when processing deeply nested schemas. An unauthenticated remote attacker can exploit this by sending a malicious request with a deeply nested JSON schema, causing the application to become unavailable.

Technologies: GGML Llama.Cpp. Vendors: GGML.

Quick answers

Is CVE-2026-52130 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-52130 being exploited in the wild.
How severe is CVE-2026-52130?: High severity, with a CVSS score of 7.5, published 1 September 2026.
Which products and versions are affected?: ggml-org llama.cpp b5693 and earlier.
Is there a fix for CVE-2026-52130?: 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-2026-52130 attacked?: It is attacked over the network.
Am I affected by CVE-2026-52130?: Check whether you run GGML Llama.Cpp. 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

The vulnerability is an uncontrolled recursion flaw in common/json-schema-to-grammar.cpp, specifically in the SchemaConverter::visit and _generate_union_rule functions. The vulnerable code lacks recursion depth limits when processing JSON schemas. An attacker can trigger a stack overflow by submitting a POST request to the /completions endpoint with a json_schema field containing deeply nested structures (≥7000 levels observed). This exhausts the thread stack and crashes the server, resulting in denial of service. The /v1/chat/completions endpoint is not affected because it routes json_schema through a Jinja engine. As of the latest release (b10405 as of August 2026), the vulnerability remains unpatched with no recursion depth controls in place.

Affected products

ggml-org llama.cpp b5693 and earlier

Timeline

2026-09-01: disclosed: Published on NVD
2026-08-12: other: Initial public disclosure on Ph4nt0m blog

References

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