When Spreadsheet Formulas Turn Deadly: This Week's Security Wake-Up Calls
When Spreadsheet Formulas Turn Deadly: This Week’s Security Wake-Up Calls
You know that feeling when you’re reviewing the week’s security news and every story makes you want to update your incident response playbook? That’s exactly where I am right now. From spreadsheets that can execute remote code to major data breaches, this week has been a masterclass in why we can never let our guard down.
The Spreadsheet That Could End Your Day
Let’s start with the most fascinating vulnerability I’ve seen in a while. Researchers at Cyera discovered a critical flaw in Grist-Core, the open-source spreadsheet-database hybrid that’s been gaining traction in enterprise environments. They’ve dubbed it “Cellbreak,” and honestly, the name fits perfectly.
The vulnerability, CVE-2026-24002, scores a hefty 9.1 on the CVSS scale, and here’s why it should make you nervous: a single malicious formula in a spreadsheet can give an attacker remote code execution. Think about how many spreadsheets flow through your organization daily. Now imagine any one of them could be weaponized with a formula that looks innocent but actually opens a backdoor to your systems.
What really gets me about this one is how it highlights our blind spots. We’ve trained users to be suspicious of email attachments and links, but who’s going to question a formula in a collaborative spreadsheet? It’s the perfect social engineering vector wrapped in a legitimate business tool.
Linux Under Fire Again
Speaking of things that should keep us up at night, we’ve got active exploitation happening against Linux systems right now. The vulnerabilities allow attackers to escalate to root privileges or completely bypass authentication through Telnet to gain shell access.
I know what you’re thinking – “Who still uses Telnet in 2026?” The unfortunate answer is more organizations than we’d like to admit. Legacy systems, industrial controls, network equipment that hasn’t been updated in years – they’re all potential targets. If you haven’t done a comprehensive audit of what’s actually running on your network lately, this might be your wake-up call.
The fact that these flaws are being actively exploited means threat actors are already incorporating them into their playbooks. This isn’t theoretical anymore – it’s happening in the wild.
Nike’s Very Bad Day
Then there’s the Nike data breach that’s making headlines. The World Leaks ransomware group claims to have dumped 1.4TB of Nike’s data, and the company is investigating. That’s not just a big number – that’s potentially years of business data, customer information, and internal communications.
What strikes me about this incident is how it demonstrates that even global brands with presumably significant security budgets aren’t immune. Ransomware groups have become increasingly sophisticated, and they’re not just encrypting data anymore – they’re exfiltrating it first to increase pressure during negotiations.
For those of us managing security programs, this reinforces why we need to assume breach mentality. It’s not about if you’ll be compromised, but when, and how quickly you can detect and respond.
The Romance Scam Evolution
On a slightly different note, there’s an interesting analysis of romance scam tactics that caught my attention. While this might seem outside our usual technical focus, these scams are increasingly being used as initial vectors for more sophisticated attacks.
We’re seeing romance scammers gather intelligence that later gets used in targeted phishing campaigns or social engineering attacks against organizations. An employee who’s been compromised personally becomes a much easier target professionally. It’s worth including this threat vector in our security awareness training.
The CVE System Needs Surgery
Finally, there’s a provocative piece arguing that MITRE has fundamentally mismanaged the CVE system and suggesting it should be handed over to private sector management. While I’m not sure privatization is the answer, the author raises valid points about the current system’s limitations.
We’ve all felt the frustration of waiting for CVE assignments, dealing with incomplete or inaccurate information, and trying to make risk decisions based on limited data. The vulnerability disclosure process needs to keep pace with how quickly threats evolve, and right now, it’s not.
What This Means for Us
Looking at these stories together, a few themes emerge. First, attack surfaces are expanding in unexpected ways – who would have thought spreadsheet formulas would become an RCE vector? Second, legacy systems continue to be our Achilles heel, whether it’s unpatched Linux boxes or organizations still running Telnet.
Most importantly, these incidents remind us why defense in depth matters. No single security control would have prevented all of these attacks, but layered defenses, proper segmentation, and rapid incident response can limit their impact.
The threat actors aren’t slowing down, and neither can we.