Exploitation observed; activity peaked at 3 mentions and remains active
Recommended action window: Immediate (within 24h)
NVD description
Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
Priority
MEDIUM
Exploitation
ACTIVE
PoC
NONE
Patch
AVAILABLE
Momentum
STABLE
If you run products in this scope, you should treat this CVE as relevant to your environment.
5 versions affected across 5 products
| Date | Total | Labels |
|---|
| 2026-02-10 | 1 | Disclosure1 |
| 2026-02-11 | 3 | Active Exploitation2Disclosure1 |
| 2026-02-13 | 1 | Disclosure1 |
| 2026-02-25 | 1 | General1 |
“Microsoft Office” proqram təminatında uzaqdan kod icrası riski yaradan təhlükəsizlik boşluğu (CVE-2026-21511) aşkarlanıb. #ETX #MilliCERT #cybersecurity #kibertəhlükəsizlik #xəbərdarlıq https://t.co/R1LliXTMNm
Post summary
A remote code execution vulnerability (CVE-2026-21511) was identified in Microsoft Office, with no PoC, exploit, or patch information provided in the tweet.
#windowsupdate #microsoft (つづき) ・CVE-2026-21238 7.8 Windows Ancillary Function Driver for WinSock ・CVE-2026-21241 7 Windows Ancillary Function Driver for WinSock ・CVE-2026-21253 7 メールスロット ファイル システム ・CVE-2026-21511 7.5 Microsoft Office Outlook
Post summary
The post enumerates several newly disclosed CVEs with associated severity scores and affected Microsoft products, but does not provide exploitation details or mitigation steps.
New CVEs: CVE-2026-21510 & CVE-2026-21511 Patching isn’t enough. Have you validated whether exploitation already occurred? Here’s how to hunt for indicators using Clear NDR: https://hubs.la/Q042Tg2x0 #NetworkSecurity #ThreatHunting #BlueTeam #NDR #CyberDefense https://t.co/rTP52UiPrQ
Post summary
The tweet announces two new CVEs and urges teams to verify if exploitation has already occurred, offering a link to a threat‑hunting tool for investigation.
https://whatsapp.com/channel/0029VbAre6eKQuJNLsryuQ0u/111 🔥 Actively Exploited / Zero-Day CVEs Patched Today. - CVE-2026-21510 - CVE-2026-21513 - CVE-2026-21519 - CVE-2026-21533 - CVE-2026-21514 - CVE-2026-21525 - CVE-2026-21511 @cyber @Cyberdost @cybertruck
Post summary
The message declares that a set of CVE-2026-215xx zero‑day vulnerabilities are actively exploited and have been patched today.
•CVE-2026-21533 – Windows Remote Desktop Services Elevation of Privilege •CVE-2026-21514 – Microsoft Word Security Feature Bypass •CVE-2026-21525 – Windows Remote Access Connection Manager DoS (exploited in the wild) •CVE-2026-21511 – Microsoft Outlook Spoofing
Post summary
The excerpt lists multiple CVEs and notes that CVE‑2026‑21525 is being actively exploited in the wild.
CVE-2026-21511 Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network. https://www.cve.org/CVERecord?id=CVE-2026-21511
Post summary
The post announces CVE-2026-21511, a deserialization flaw in Microsoft Office Outlook that permits network spoofing; no PoC, exploit, or patch information is provided.
15 of 15 entries
| Part | Vendor | Product | Version | Target SW | Target HW |
|---|---|---|---|---|---|
| App | microsoft | 365_apps | - | - | x64 |
| App | microsoft | 365_apps | - | - | x86 |
| App | microsoft | office | 2019 | - | x64 |
| App | microsoft | office | 2019 | - | x86 |
| App | microsoft | office_long_term_servicing_channel | 2021 | - | x64 |
| App | microsoft | office_long_term_servicing_channel | 2021 | - | x86 |
| App | microsoft | office_long_term_servicing_channel | 2021 | macos | - |
| App | microsoft | office_long_term_servicing_channel | 2024 | - | x64 |
| App | microsoft | office_long_term_servicing_channel | 2024 | - | x86 |
| App | microsoft | office_long_term_servicing_channel | 2024 | macos | - |
| App | microsoft | sharepoint_server | - | - | - |
| App | microsoft | sharepoint_server | 2016 | - | - |
| App | microsoft | sharepoint_server | 2019 | - | - |
| App | microsoft | word | 2016 | - | x64 |
| App | microsoft | word | 2016 | - | x86 |