Google's Threat Intelligence Group says it caught the first known case of a real attacker using a large language model to find and weaponize a zero-day - a 2FA bypass in a popular but unnamed open-source web-based system administration tool. Google has high confidence the Python exploit was AI-generated, citing textbook code structure, abundant educational docstrings, and a hallucinated CVSS score in the script. The flaw was a high-level logic bug, the kind LLMs excel at spotting, rather than a memory corruption issue. Google rules out Gemini and warns that AI-assisted exploit development is being industrialized via account-pooling and proxy relays for premium models.
Ivanti disclosed Wednesday that attackers are exploiting a zero-day in Endpoint Manager Mobile (EPMM) to gain admin-level remote code execution on enterprise MDM servers. CVE-2026-6973. Successful exploitation gives the attacker control over the MDM platform that pushes apps and configurations to managed mobile fleets - a foothold that can pivot into managed devices and the corporate identity layer. CISA added the flaw to its Known Exploited Vulnerabilities catalog the same day with a federal patch deadline next week. Ivanti products have a long history of zero-day exploitation.
Palo Alto Networks confirmed Wednesday that attackers are exploiting a zero-day in its firewall login portal to run code as root on PA-Series and VM-Series firewalls. CVE-2026-0300 (CVSS 9.3) is a buffer overflow in the User-ID Authentication Portal (Captive Portal) that lets unauthenticated attackers send crafted packets and execute code without any login. Palo Alto Unit 42 attributed the activity to CL-STA-1132, a likely state-sponsored cluster that started probing on April 9 and achieved RCE a week later. Attackers deploy tunneling tools and enumerate Active Directory using the firewall's service account. First patches arrive May 13. Shadowserver counts 5,800+ exposed VM-Series firewalls.
Shadowserver data shows 1,300+ internet-exposed Microsoft SharePoint servers remain unpatched against CVE-2026-32201, a spoofing flaw Microsoft confirmed as a zero-day and CISA added to its Known Exploited Vulnerabilities catalog the same day the fix dropped in April Patch Tuesday. Fewer than 200 systems have been patched since the update shipped last week. The flaw affects SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition. An unauthenticated attacker can perform network spoofing through improper input validation in a low-complexity attack that needs no user interaction, letting them view sensitive information and modify data, though not affect availability. Microsoft has not described the exploitation technique or attributed the attacks to a specific group, which is unusual for a zero-day and hints at an ongoing investigation. CISA ordered federal agencies to patch by April 28 under Binding Operational Directive 22-01, and given ongoing in-the-wild abuse, private-sector operators should treat that as their own deadline. SharePoint's habit of holding cached Office 365 tokens, SharePoint-signed refresh tokens, and IP on sensitive business processes makes any compromise a serious lateral-movement foothold, not a minor information disclosure.
Just days after Microsoft patched BlueHammer (CVE-2026-33825) in Tuesday's Patch Tuesday, the same researcher 'Chaotic Eclipse' (aka Nightmare-Eclipse) has released a second Microsoft Defender local privilege escalation zero-day called RedSun. The exploit works on fully-patched Windows 10, Windows 11, and Windows Server systems with Windows Defender enabled, even after installing this week's April updates. The flaw abuses Defender's cloud file rollback behavior: when Defender detects a file with a 'cloud tag' it tries to restore it to its original location without validating the target path. The exploit uses NTFS junctions and opportunistic locks to redirect the write to C:\Windows\System32, overwriting system files like TieringEngineService.exe to gain SYSTEM privileges. Huntress Labs is reporting all three recently-leaked Windows Defender zero-days (BlueHammer, RedSun, and UnDefend) are now being exploited in the wild. The researcher has threatened to drop more severe RCE exploits in protest of how Microsoft handled their disclosure process. No patch available for RedSun yet. Working PoC code is public on GitHub.
Adobe has released an emergency security update (APSB26-43, priority-1) to patch CVE-2026-34621, the Adobe Reader zero-day we reported on April 10 that had been exploited since December 2025 via malicious PDF documents. The flaw has now been classified as a prototype pollution vulnerability leading to arbitrary code execution - more severe than the initial fingerprinting and data theft we described. Adobe confirmed it's worse than just information leakage: the underlying bug can achieve full RCE, not just the reconnaissance stage observed in early exploitation. CVSS was initially scored 9.6 but Adobe revised it down to 8.6 after changing the attack vector from Network to Local. EXPMON researcher Haifei Li, who first disclosed the flaw, was credited by Adobe. All users on Windows and macOS should update immediately - Adobe assigned this patch its highest priority rating.
An unpatched zero-day in Adobe Acrobat Reader has been actively exploited since at least November 2025 using booby-trapped PDF documents. The exploit, discovered by EXPMON researcher Haifei Li, works on the latest version of Adobe Reader without any user interaction beyond opening the file. It abuses privileged Acrobat JavaScript APIs (util.readFileIntoStream and RSS.addFeed) to silently harvest local files, OS details, language settings, and the Reader version from the victim's machine, then sends everything to an attacker-controlled server. The PDFs use Russian-language lures related to the oil and gas industry. The attack is a two-stage operation: the first pass fingerprints the target, and if the system meets the attacker's criteria, a follow-on RCE or sandbox escape payload is delivered. Only 5 out of 64 antivirus engines on VirusTotal detected the sample. No CVE has been assigned and no patch is available.
A frustrated security researcher published working exploit code for an unpatched Windows local privilege escalation flaw after Microsoft's Security Response Center mishandled the disclosure. The researcher, posting as Chaotic Eclipse, dropped the proof-of-concept on GitHub on April 3 with the message "I was not bluffing Microsoft." Will Dormann of Tharsos confirmed the exploit works - it combines a TOCTOU race condition with path confusion to access the SAM database containing local account password hashes, enabling escalation to SYSTEM privileges. The exploit is confirmed working on Windows desktop but unreliable on Windows Server. The researcher deliberately included bugs in the PoC, but the underlying technique is now public and weaponizable.
Microsoft Threat Intelligence published a detailed report on Storm-1175, a China-based financially motivated group that deploys Medusa ransomware at extreme speed - sometimes moving from initial access to full ransomware deployment within 24 hours. The group exploits internet-facing systems using a mix of zero-day and recently disclosed (n-day) vulnerabilities, having weaponized over 16 flaws across 10 products since 2023. Two vulnerabilities were exploited as zero-days a full week before public disclosure. Recent targets include healthcare, education, finance, and professional services organizations in the US, UK, and Australia. Their playbook: exploit a web-facing flaw, create persistence via new accounts and web shells, steal credentials with Mimikatz, disable Defender via registry modifications, exfiltrate data with Rclone, then deploy Medusa across the network.
If you patched FortiClient EMS for CVE-2026-21643 two weeks ago by upgrading to 7.4.5, you're now vulnerable to a new zero-day. CVE-2026-35616 is a CVSS 9.1 pre-authentication API access bypass affecting versions 7.4.5 and 7.4.6 - the exact versions customers upgraded to. Defused Cyber spotted exploitation in the wild starting March 31. Fortinet released an emergency weekend hotfix on Saturday, with watchTowr noting attackers deliberately timed this for the Easter holiday when security teams are at half strength.
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