Stephen Fewer

@stephenfewer.bsky.social

Senior Principal Security Researcher at @rapid7.com. Specializing in software vulnerabilities and exploitation. stephenfewer.github.io

Check out the analysis by @cryptocat.me for CVE-2026-20127 in Cisco SD WAN. That other PoC posted last week exploits a totally different bug that doesn't match the reported IOCs (some kind of file upload due to path traversal in vManage maybe). We asses with high confidence this is CVE-2026-20127 🔥

CryptoCat@cryptocat.me · 5mo ago

🚨 CVE-2026-20127: Cisco SD-WAN authentication bypass. An unauthenticated attacker can inject SSH keys without crypto verification via a flawed state machine. Active exploitation by UAT-8616 since 2023 💀 Check out the full @rapid7.com analysis 👇 attackerkb.com/topics/bP3FM...

We just published our @rapid7.com analysis of CVE-2026-1731, a critical command injection affecting BeyondTrust Privileged Remote Access (PRA) & Remote Support (RS). Unauthenticated RCE, with a root cause due to Bash arithmetic evaluation. Analysis/PoC here: attackerkb.com/topics/jNMBc...

CVE-2026-1731 | AttackerKB

On February 6, 2026, BeyondTrust published an advisory for a new critical command injection vulnerability, CVE-2026-1731, affecting their products Remote Suppo…

attackerkb.com

⚠️ In Aug. 2025, Rapid7 found #TwonkyServer susceptible to multiple vulns – granting unauthenticated attackers plaintext admin credentials, full admin access to the instance & control of all stored media files. At the time of publication, these vulns have not been patched. Read on: r-7.co/4a0JiuU

CVE-2025-13315, CVE-2025-13316: Critical Twonky Server Authentication Bypass (NOT FIXED)

Rapid7 has identified two vulnerabilities that facilitate administrator authentication bypass in Twonky Server, a media solution.

r-7.co

As Pwn2Own Ireland 2025 draws to a close, a huge thank you to @thezdi.bsky.social for putting on another great contest! I reflected on why @rapid7.com has taken part at #Pwn2Own over the last two years, and our successes so far in the world of competitive zero day exploit development r-7.co/4o6RM85

Rapid7 at Pwn2Own: Raising the Bar in Vuln Intel

As the 2025 edition of Pwn2Own Ireland draws to a close, we are taking a beat to reflect on Rapid7’s participation & achievements in the world of competitive zero day exploit development.

r-7.co

We have published our AttackerKB @rapid7.com Analysis for the recent GoAnywhere MFT vuln, CVE-2025-10035. It's an access control bypass + unsafe deserialization + an as-yet unknown issue in how an attacker can know a specific private key! attackerkb.com/topics/LbA9A...

CVE-2025-10035 | AttackerKB

On September 18, 2025, Fortra published a security advisory for a new vulnerability affecting their managed file transfer product, GoAnywhere MFT. The new vuln…

attackerkb.com

⚠️ Rapid7 has identified a permission bypass vuln. in multiple versions of #OnePlus OxygenOS installed on its Android smartphones. When leveraged, any app on the device may read SMS/MMS data & metadata via the default Telephony provider. More in our blog: r-7.co/42EujlR

Come join @rapid7.com ! I’m hiring for a Senior Security Researcher to join our team. You'll get to work on n-day analysis, zero-day research, exploit development, and more - focusing on enterprise software and appliances. Fully remote in the UK, more details here: careers.rapid7.com/jobs/senior-...

Senior Security Researcher - United Kingdom

The Senior Security Researcher will drive vulnerability discovery and analysis within Rapid7’s Vulnerability Intelligence team. You’ll research zero-day and n-day threats, develop exploits, publish ro...

careers.rapid7.com

Today @rapid7.com is disclosing 8 new vulnerabilities affecting 742 models across 4 vendors. After 13 months of coordinated disclosure with Brother Industries, Ltd, we're detailing all issues including a critical auth bypass. Full details here: www.rapid7.com/blog/post/mu...

Rapid7

Rapid7 conducted a zero-day research project into multifunction printers (MFP) from Brother Industries, Ltd. This research resulted in the discovery of 8 new vulnerabilities.

rapid7.com

Today @rapid7.com disclosed two vulns affecting NetScaler Console and SDX, found by Senior Security Researcher Calum Hutton! 🎉 Our blog details the authenticated arbitrary file read vuln (CVE-2025-4365), and the authenticated arbitrary file write vuln (Which the vendor has not assigned a CVE for).

Rapid7@rapid7.com · last yr.

During root cause analysis for the #NetScaler Console vulnerability, CVE-2024-6235, Rapid7 discovered & disclosed to the vendor 2 additional high severity vulnerabilities. Find exploitation details, remediation advice & more in a new blog: r-7.co/4efpR1S

A new @rapid7.com Analysis of CVE-2024-58136 was just published to AttackerKB, courtesy of Calum Hutton 🔥 Affecting the Yii framework, this analysis details the root cause of CVE-2024-58136, and how it can be leveraged for RCE via a dirty file write to a log file. attackerkb.com/topics/U2Ddo...

CVE-2024-58136 | AttackerKB

Yii framework is a component-based MVC web application framework, providing developers with the building blocks to create complex web applications including mo…

attackerkb.com

We have just published our AttackerKB @rapid7.com Analysis of CVE-2025-22457, an unauthenticated stack based buffer overflow in Ivanti Connect Secure. Difficult to exploit due to severe character restrictions, we detail our full RCE technique here: attackerkb.com/topics/0ybGQ...

CVE-2025-22457 | AttackerKB

On April 3, 2025, Ivanti published an advisory for CVE-2025-22457, an unauthenticated remote code execution vulnerability due to a stack based buffer overflow.…

attackerkb.com