Ethical Hacking News
A critical vulnerability has been discovered in the Brotli decoder, a widely used compression format, leaving users of multiple software platforms at risk. The vulnerability, known as CVE-2026-111497, can potentially allow an attacker to execute arbitrary code on a system. Updates and patches are available, and users can take steps to protect themselves by updating to the latest versions and disabling Brotli decompression if it is not needed.
A critical flaw in the Brotli decoder has been discovered, allowing for crafted compressed data to overwrite past the end of a buffer and corrupt a program's memory.The vulnerability affects multiple software, including Node.js, Bun, Python, and Envoy proxies.The impact of the vulnerability is significant, as it can potentially allow an attacker to execute arbitrary code on a system.Updates and patches are available for all affected software, and users can take steps to protect themselves by updating to the latest versions and disabling Brotli decompression if it is not needed.
A recent discovery has revealed a critical flaw in the Brotli decoder, a compression format widely used across the web to shrink pages and other traffic. The vulnerability, identified as CVE-2026-111497, allows for crafted compressed data to overwrite past the end of a buffer and corrupt a program's memory, potentially causing a crash, a memory leak, or the execution of attacker-controlled code. The flaw was first disclosed on October 21, when Node.js and Google shipped fixes, and more have followed product by product since.
The vulnerability affects multiple software, including Node.js, Bun, Python, and Envoy proxies. In Node.js, the vulnerability was discovered in versions 22.x, 24.x, and 26.x before the fix was released, while the latest versions available are 22.23.4, 24.22.1, and 26.12.1. In Python, the risk comes from the Brotli or brotlicffi packages being installed at all, as HTTP clients such as requests, urllib3, httpx, and aiohttp decode Brotli responses on their own.
The vulnerability is not limited to the software packages themselves, but also affects Envoy and Istio, which are only affected if Brotli decompression is enabled. This means that even if the software is not actively using the Brotli decompressor, it can still be exploited if it is configured to do so. In the case of Envoy, only specific versions are affected, and the vulnerability is only exploitable if the Brotli decompressor is configured.
The impact of the vulnerability is significant, as it can potentially allow an attacker to execute arbitrary code on a system. In the case of Node.js, the vulnerability can be exploited by reading a Brotli-compressed response or by fetching a Brotli-compressed response. In Python, the risk comes from the Brotli or brotlicffi packages being installed at all, and the vulnerability can be exploited by reading a Brotli-compressed response.
The good news is that updates and patches are available for all affected software, and users can take steps to protect themselves by updating to the latest versions and disabling Brotli decompression if it is not needed. However, the vulnerability highlights the importance of keeping software up-to-date and being aware of the potential risks associated with the use of compression formats.
The Brotli decoder flaw is a reminder of the need for vigilance and proactive security measures in the digital world. As software and systems become increasingly interconnected, the potential risks associated with vulnerabilities like this one become more significant. By staying informed and taking steps to protect ourselves, we can minimize the impact of such vulnerabilities and stay safe online.
Related Information:
https://www.ethicalhackingnews.com/articles/Brotli-Decoder-Flaw-Exposes-Vulnerability-in-Multiple-Software-Leaving-Users-at-Risk-ehn.shtml
https://thehackernews.com/2026/10/brotli-decoder-flaw-behind-nodejs-rce.html
https://nvd.nist.gov/vuln/detail/CVE-2026-111497
https://www.cvedetails.com/cve/CVE-2026-111497/
Published: Sat Oct 24 06:49:35 2026 by llama3.2 3B Q4_K_M
