cbcvebase.
CVE-2026-21510
published 2026-02-10

CVE-2026-21510: Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.

PriorityP188high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
KEVITW
CISA Known Exploited Vulnerabilitydue 2026-03-03
Exploited in the wild
EPSS
25.84%
97.7th percentile
Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.

Affected

42 ranges· showing 25
VendorProductVersion rangeFixed in
microsoftwindows_10_1607< 10.0.14393.886810.0.14393.8868
microsoftwindows_10_1809< 10.0.17763.838910.0.17763.8389
microsoftwindows_10_21h2< 10.0.19044.693710.0.19044.6937
microsoftwindows_10_22h2< 10.0.19045.693710.0.19045.6937
microsoftwindows_10_version_1607>= 10.0.14393.0 < 10.0.14393.886810.0.14393.8868
microsoftwindows_10_version_1809>= 10.0.17763.0 < 10.0.17763.838910.0.17763.8389
microsoftwindows_10_version_21h2>= 10.0.19044.0 < 10.0.19044.693710.0.19044.6937
microsoftwindows_10_version_22h2>= 10.0.19045.0 < 10.0.19045.693710.0.19045.6937
microsoftwindows_11_23h2< 10.0.22631.664910.0.22631.6649
microsoftwindows_11_24h2< 10.0.26100.778110.0.26100.7781
microsoftwindows_11_25h2< 10.0.26200.778110.0.26200.7781
microsoftwindows_11_version_22h3>= 10.0.22631.0 < 10.0.22631.664910.0.22631.6649
microsoftwindows_11_version_23h2>= 10.0.22631.0 < 10.0.22631.664910.0.22631.6649
microsoftwindows_11_version_24h2>= 10.0.26100.0 < 10.0.26100.784010.0.26100.7840
microsoftwindows_11_version_25h2>= 10.0.26200.0 < 10.0.26200.784010.0.26200.7840
microsoftwindows_11_version_26h1>= 10.0.28000.0 < 10.0.28000.157510.0.28000.1575
microsoftwindows_server_2012
microsoftwindows_server_2012>= 6.2.9200.0 < 6.2.9200.259236.2.9200.25923
microsoftwindows_server_2012_r2>= 6.3.9600.0 < 6.3.9600.230226.3.9600.23022
microsoftwindows_server_2016< 10.0.14393.886810.0.14393.8868
microsoftwindows_server_2016>= 10.0.14393.0 < 10.0.14393.886810.0.14393.8868
microsoftwindows_server_2019< 10.0.17763.838910.0.17763.8389
microsoftwindows_server_2019>= 10.0.17763.0 < 10.0.17763.838910.0.17763.8389
microsoftwindows_server_2022< 10.0.20348.471110.0.20348.4711
microsoftwindows_server_2022>= 10.0.20348.0 < 10.0.20348.477310.0.20348.4773

Detection & IOCsextracted from sources · hover to see the quote

filenamemalicious Windows Shortcut (LNK) file
filename.cpl
command\\attacker.com\share\payload.cpl
  • Hunt for auto-parsed LNK files that trigger SMB connections without user interaction — the exploit requires no click from the victim to initiate NTLM authentication to the attacker's server.
  • Alert on Net-NTLMv2 hash capture attempts originating from Windows Shell / LNK file processing, which may indicate exploitation of CVE-2026-21510 or its incomplete-patch follow-on CVE-2026-32202.
  • Attribute LNK-based SmartScreen bypass activity to APT28 (Fancy Bear / Forest Blizzard / GruesomeLarch / Pawn Storm) when targeting Ukraine and EU nations, as this group chained CVE-2026-21510 with CVE-2026-21513 (MSHTML Framework bypass).
  • Flag opening of specially crafted LNK or shortcut files as a potential trigger for CVE-2026-21510 exploitation — user interaction is limited to opening the file.
  • ·CVE-2026-21510 was patched in February 2026 (KB articles listed in MSRC advisory), but the patch was incomplete — it mitigated RCE but left an authentication coercion path (CVE-2026-32202) that was only addressed in April 2026. Ensure both patches are applied.
  • ·CVE-2026-21510 was exploited as a zero-day chained with CVE-2026-21513 (MSHTML Framework Security Feature Bypass, CVSS 8.8, also fixed February 2026); both must be patched together to fully remediate the APT28 exploit chain.
  • ·CISA KEV remediation deadline for CVE-2026-21510 was 2026-03-03; FCEB agencies must verify compliance.

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
vulncheck8.8HIGH
cisa8.8HIGH
vendor_msrc8.8HIGH
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