Vulnerability report

Trusted Third Party Report High Confidence Not in CISA KEV

CVE-2026-51990

Sogou Input Method for Windows

Tencent / Sogou / Sogou Input Method for Windows

Watch CVE-2026-51990 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
High
Exploit status
Trusted Third Party Report
EPSS
0.9%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-51990 is an unauthenticated vulnerability affecting Tencent / Sogou Sogou Input Method for Windows.

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Also reported by third-party sources. Confidence is high.

Who is affected?

Tencent / Sogou / Sogou Input Method for Windows.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Sogou Input Method for Windows

An issue in Sogou Sogou Input Method < 16.3.0.3498 (fixed in 16.3.0.3498) allows a remote attacker to execute arbitrary code via the biz_helper.exe component

Published
16 Sep 2026
Exploitation Attempts Reported
14 Sep 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

windows

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

Gen

Recorded 14 Sep 2026

A trusted third party reported exploitation attempts.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Gen First 2026-09-14 13:33 UTC

Operational indicators for this CVE are listed under Detection.

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Indicators of Compromise (IoCs)

Operational indicators linked to exploitation of this CVE. IoCs age over time, especially IP addresses.

Export
Type Indicator First Seen Last Seen Age Source
File hash Stale 29c7ee41d0cc9e07d981e451df56d0c3d37c41ac4ec10c7b516cc033ee397a63

SHA256

 2026-04-09 13:37 UTC 2026-04-09 13:37 UTC 7 months ago Source
File hash Stale 749160a2f20f82744026719cf72e483595c6aad718efa74d675a98662e02422e

SHA256

 2026-04-09 13:37 UTC 2026-04-09 13:37 UTC 7 months ago Source
File hash Stale d7a3c7eb94edc0e020f74c678743d71d61e944634aade4a67a96c3589e828b3a

SHA256

 2026-04-09 13:37 UTC 2026-04-09 13:37 UTC 7 months ago Source
IP Stale 8.218.50.207 2026-04-09 13:36 UTC 2026-04-09 13:36 UTC 7 months ago Source
Domain Stale mail.uaiubifas.top 2026-04-09 13:34 UTC 2026-04-09 13:34 UTC 7 months ago Source
Domain Stale noht1ng.top 2026-04-09 13:34 UTC 2026-04-09 13:34 UTC 7 months ago Source

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.9%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Control of Generation of Code ('Code Injection') CWE-94

Recent mention · The Hacker News

China-Aligned Hackers Hijack Sogou Input Method DNS Requests to Deploy DarkVigil Backdoor

Ravie LakshmananNov 04, 2026Vulnerability / Malware A China-aligned threat actor known as SlippyNunchucks has been attributed to a Domain Name System (DNS) hijacking operation abusing insecure HTTP communications in Windows versions of Sogou Input Method as part of a...

Read full advisory

All Mentions

Recent mention · The Hacker News

China-Aligned Hackers Hijack Sogou Input Method DNS Requests to Deploy DarkVigil Backdoor

The Hacker News · 04 Nov 2026

Ravie LakshmananNov 04, 2026Vulnerability / Malware A China-aligned threat actor known as SlippyNunchucks has been attributed to a Domain Name System (DNS) hijacking operation abusing insecure HTTP communications in Windows versions of Sogou Input Method as part of a surveillance campaign designed to deploy an implant called DarkVigil (aka FDMTP). The campaign, observed starting July 1, 2026, is assessed to have targeted organizations and Chinese-speaking individuals in Hong Kong, Thailand, Japan, Vietnam, Oman, and Sri Lanka, according to ESET. "DarkVigil implants are typically deployed...

Recent mention · BleepingComputer

Hackers exploit Tencent app flaw to deploy GrayRabbit malware

BleepingComputer · 13 Sep 2026

Threat actors linked to a China-aligned espionage group are exploiting a critical vulnerability (CVE-2026-51990) in Tencent's Sogou Input Method for Windows to deploy the GrayRabbit backdoor. [...]

Timeline

From disclosure to observed exploitation attempts

  1. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  2. 13:33 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party report of exploitation attempts

  3. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

  4. 13:34 UTC

    Indicators of compromise added (6)

    Indicators of compromise recorded

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-51990

Sample API response 
{
  "cve_id": "CVE-2026-51990",
  "confidence": "High",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.00926,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}