Vulnerability report

Trusted Third Party Report Confirmed Confidence In CISA KEV

CVE-2023-41763

Skype for Business Elevation of Privilege Vulnerability

Microsoft / Skype for Business Server 2015 CU13 · affected before 6.0.9319.869

Watch CVE-2023-41763 Browse KEV feed
Severity
CVSS 5.3 · Medium
Confidence
Confirmed
Exploit status
Trusted Third Party Report
EPSS
90.3%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-41763 is an unauthenticated Skype for Business Elevation of Privilege Vulnerability affecting Microsoft Skype for Business Server 2015 CU13, Skype for Business Server 2019 CU7.

Have exploitation attempts been observed?

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

Who is affected?

Microsoft / Skype for Business Server 2015 CU13 and Skype for Business Server 2019 CU7, including affected before 6.0.9319.869 and affected before 7.0.246.530.

What should we do?

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

Overview

Skype for Business Elevation of Privilege Vulnerability

Skype for Business Elevation of Privilege Vulnerability

Microsoft Affected
Skype for Business Server 2015 CU13
Before 6.0.9319.869
Microsoft Affected
Skype for Business Server 2019 CU7
Before 7.0.246.530
View vendor advisory (opens in new tab)
Published
10 Oct 2023
Exploitation Attempts Reported
10 Oct 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner cisa microsoft

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

CISA

Recorded 10 Oct 2023

A trusted third party reported exploitation attempts.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

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
CISA First 2023-10-10 00:00 UTC
The Shadowserver 2026-09-21 00:00 UTC

Detection

Operational artifacts and observed signals

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

Virtual patch status

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

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-41763.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

5.3 Medium

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:L/I:N/A:N

EPSS

90.3%

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

Weaknesses

Server-Side Request Forgery (SSRF) CWE-918

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Skype for Business 2019 (SfB) - Blind Server-side Request Forgery

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation attempts

  1. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attempts reported by an external source

  2. 14:20 UTC

    Public PoC available

    Public proof-of-concept code published

  3. 00:00 UTC

    Nuclei template available

    Scanner coverage available

  4. 17:07 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  6. 23:08 UTC

    CVE ID reserved

    Identifier reserved by the CNA

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.

Start 14-day Pro trial Read API docs
  • 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-2023-41763

Sample API response 
{
  "cve_id": "CVE-2023-41763",
  "confidence": "Confirmed",
  "cvss_score": 5.3,
  "cvss_estimated": false,
  "epss_score": 0.90282,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}