#patch

A flaw in Google's reference C decoder for Brotli, the compression format many websites use, lets crafted compressed data write past the end of a buffer, which can crash a program, leak memory or, in some setups, run code. Node.js disclosed it on October 21 with credit to OpenAI's Codex Security researchers; the fix was in Brotli's source in February, but nobody knew then it was a security bug, The Register reports.

This week the fallout spread. Microsoft shipped out-of-band .NET updates on October 25, and Palo Alto Networks rolled out hotfixes for PAN-OS firewalls that inspect Brotli traffic. According to the Broccoli2Shell site, threat-intelligence firm ELLIO saw exploit traffic using the public proof of concept on October 26, and CISA added CVE-2026-111497 to its exploited-vulnerabilities catalog on October 27.

Anything that decompresses Brotli data from others with Brotli 1.0.3 to 1.2.0 can be exposed, including Node's built-in fetch and Python's requests when a Brotli package is installed. Patched programs must also be restarted, and container images rebuilt.

New this week on PHP2Shell, the two critical PHP flaws patched on October 21: on Monday, October 26, the US Cybersecurity and Infrastructure Security Agency (CISA) added both (CVE-2026-109618 and CVE-2026-109619) to its catalog of exploited vulnerabilities and gave federal agencies until October 29 to patch, The Register reports. A Perplexity researcher logged successful shell commands on honeypots, while Sophos and Palo Alto Networks walked back earlier claims of successful attacks.

On October 28, Israeli security company Dream said it had recovered the tools of a suspected Chinese, apparently AI-assisted campaign that chained a custom PHP2Shell exploit with a Linux kernel bug (Fragnesia, CVE-2026-46300) to get root on 25 Palo Alto Networks PAN-OS firewalls and management servers in the US, Japan, Taiwan and South Korea. From a US government-affiliated firewall, Dream says, the attackers moved into the internal network and went after Active Directory. Palo Alto's Unit 42 independently verified the tooling, and Palo Alto is releasing fixed PAN-OS versions.

Admins are told to move to PHP 8.5.12, 8.4.27, 8.3.36 or 8.2.35, and to keep management interfaces off the internet.

Tailscale, a popular VPN-style networking service, released client version 1.104.4 to fix four security bulletins in Tailscale SSH and related features, after a researcher, Erica Windisch of Cyberdione Labs, published a report called Tailworm, The Hacker News reports.

The main flaw was in socket forwarding: the server checked a path and then acted as root, and a timing trick could swap the path in between. An attacker who already controls a device allowed to open SSH sessions could reach root-only sockets such as Docker's, which in Windisch's tests gave a root shell. Tailscale says the flaws do not let an unauthenticated attacker connect to arbitrary servers. The fix runs forwarding as the logged-in user.

Tailscale recommends updating, tightening SSH access rules, and, where an update must wait, setting TS_SSH_DISABLE_FORWARDING=1, which it says blocks several of the more serious findings without turning off Tailscale SSH.