# CVE-2026-78659: Go net/http HTTP/2 server memory exhaustion

Source: https://junglewise.ai/threats/cve-2026-78659-go-2026-6603-http-2-server-memory-exhaustion-due-to-trailer  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-08. Updated: 2026-10-10  
License: CC BY 4.0 with a link back

CVE-2026-78659 · Severity: high · CVSS 7.5 · Published 2026-10-08

Go's HTTP/2 server implementation in the net/http library can be exhausted of memory when processing specially crafted Trailer headers. An attacker on the network can send malicious HTTP/2 requests to cause the server to consume excessive memory, potentially leading to denial of service by exhausting available resources and crashing the service.

Technologies: [net/http (Go)](https://junglewise.ai/threats/technologies/net-http). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-78659 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-78659 being exploited in the wild.

**How severe is CVE-2026-78659?** High severity, with a CVSS score of 7.5, published 8 October 2026.

**Which products and versions are affected?** Go net/http.

**Is there a fix for CVE-2026-78659?** 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-2026-78659 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-78659?** Check whether you run net/http (Go). 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 HTTP/2 server in Go's net/http package fails to properly limit memory consumption when processing Trailer headers, allowing an attacker to craft requests that cause unbounded memory allocation. The vulnerability is triggered via network-based HTTP/2 requests without requiring authentication or user interaction. A fix has been made available through Go commits addressing memory management in HTTP/2 trailer handling.

## Affected products

- Go net/http

## Identifiers

- CVE-2026-78659
- GO-2026-6603

## Timeline

- 2026-10-08: disclosed

## References

- [https://go.dev/cl/847185](https://go.dev/cl/847185)
- [https://go.dev/cl/847314](https://go.dev/cl/847314)

## Related threats

- [GO-2024-2687 - HTTP/2 CONTINUATION flood in net/http](https://junglewise.ai/threats/cve-2023-45288-net-http-x-net-http2-close-connections-when-receiving-too-many)
- [GO-2021-0141 - A Go HTTP server which reads from the request body while simultaneously writing a response can panic…](https://junglewise.ai/threats/go-2021-0141-a-go-http-server-which-reads-from-the-request-body-while-5e2babd1)