Vulnerability in Microsoft Windows Folder Redirection (CVE-2021-26887)
Summary
Vulnerability in Microsoft Windows Folder Redirection (CVE-2021-26887). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
Microsoft Windows Folder Redirection Elevation of Privilege Vulnerability
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A weakness called CVE-2021-26887 was discovered in Microsoft Windows Folder Redirection.
Severity is High (CVSS 7.8/10). If exploited, attackers can leak data or disrupt key functionality.
What you should do: update the affected software to the latest version. If unsure, ask your IT team or search the vendor's site for "Microsoft Windows Folder Redirection CVE-2021-26887".
CVE-2021-26887 (Microsoft Windows Folder Redirection). Severity: High / CVSSv3 7.8. Category: CWE-59.
Response plan:
- Check the vendor advisory for affected versions and the patched release.
- If a vulnerable version is running in production, schedule maintenance (urgency from KEV/CVSS).
- If no patch yet, mitigate via WAF rule, disabling the affected feature, etc.
- Monitor logs / SIEM for known IOC and PoC signatures of this CVE.
PoCs and fix commits: see the 'References' section, MITRE, and NVD.
A weakness (CVE-2021-26887) in Microsoft Windows Folder Redirection. A serious software flaw has been identified.
Target versions of Microsoft Windows Folder Redirection (see vendor advisory). If running in production, identify exposure immediately.
Severity: High (CVSS 7.8/10). If exploited, attackers can leak data or disrupt key functionality.
Update to the patched release as listed in the vendor advisory. (Typical mitigation pattern for CWE-59)
If a patch is not yet available, consider disabling the affected feature, applying WAF rules, blocking via network ACLs, or isolating the vulnerable version.
Check version information, scan dependencies via SBOM, and monitor SIEM for IOC and PoC signatures related to this CVE.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'microsoft' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
microsoftを grep し、稼働しているサービス・バージョンを把握する。 -
7Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 3 と同じログクエリでアラート再発が無いか継続監視。
References
- web msrc.microsoft.com
- web portal.msrc.microsoft.com
- web nvd.nist.gov
- web github.com