---
id: "CVE-2026-123610"
page: "https://infrastack.ai/live/CVE-2026-123610"
kind: "vulnerability"
aliases: ["CVE-2026-123610"]
title: "rustls: Brotli certificate decompression lets a peer exhaust memory"
severity: "medium"
cvss: 6.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "rust", "rustls", "self-hosted", "tls"]
not_affected_if: ["brotli-feature-disabled", "default-config"]
published_at: "2026-11-08T02:16:56+00:00"
first_seen_at: "2026-11-08T02:21:14+00:00"
updated_at: "2026-11-08T02:24:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123610", "first_seen_at": "2026-11-08T02:21:14+00:00"}]
exploit_sources: []
---

# rustls: Brotli certificate decompression lets a peer exhaust memory

Link for people: https://infrastack.ai/live/CVE-2026-123610 (this .md is for agents)

rustls before 0.23.46 accepts an oversized Brotli history window in optional certificate decompression. A malicious peer can send a tiny certificate header before authentication that requests up to 1 GiB and aborts the client or server process.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the locked rustls version in `Cargo.lock` for `rustls` below `0.23.46`.
- Check whether the build enables Brotli certificate decompression (the optional rustls feature for certificate compression).

## Fix

- `rustls` moves to `0.23.46` or later.

## Timeline

- 2026-11-08T02:21:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123610

## Documents

- [advisory] Vendor advisory: github.com https://github.com/rustls/rustls/security/advisories/GHSA-h2v8-394m-p7vv
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/rustls-before-0.23.46-denial-of-service-via-brotli-certificate-decompression

## From the sources

rustls before 0.23.46 contains an uncontrolled memory allocation flaw in its optional Brotli certificate decompression, which limits decompressed output size but accepts an input-selected large history window. Malicious peers can send a certificate with a five-byte Brotli header requesting up to 1 GiB before authentication, aborting Brotli-enabled clients or client-authenticating servers whose allocator cannot satisfy the request.

---

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