CVE-2025-48802VulnerabilityPublished 8 Jul 2025Updated 13 Feb 2026

CVE-2025-48802: Microsoft Windows 11 version 22H2 · Improper Certificate Validation

Affects Microsoft Windows 11 version 22H2Source CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.9% chance of exploitation in 30 days – higher than 59% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Base metrics

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Temporal metrics

Exploit Code Maturity: Unproven
Remediation Level: Official Fix
Report Confidence: Confirmed

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.
Exploit Code Maturity: Unproven: No exploit code is available, or an exploit is theoretical.
Remediation Level: Official Fix: A complete vendor solution is available. Either the vendor has issued an official patch, or an upgrade is available.
Report Confidence: Confirmed: Detailed reports exist, or functional reproduction is possible (functional exploits may provide this). Source code is available to independently verify the assertions of the research, or the author or vendor of the affected code has confirmed the presence of the vulnerability.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Microsoft Windows 11 version 22H2	Affected =10.0.22621.0	Fixed in–

AI-suggested

1. Restrict SMB protocol access to trusted networks and devices only, using network segmentation and firewall rules to limit exposure. 2. Monitor SMB traffic for unusual patterns or anomalies that could indicate spoofing attempts, employing intrusion detection/prevention systems with SMB protocol awareness. 3. Enforce strict access controls and least privilege principles to minimize the number of users or services with SMB access rights. 4. Prepare for rapid deployment of official patches from Microsoft once released, including testing in controlled environments to ensure compatibility. 5. Consider deploying additional network-level encryption or authentication mechanisms where feasible to supplement SMB security. 6. Educate IT and security teams about the vulnerability specifics to enhance detection and response capabilities. 7. Regularly audit and update certificate management policies to ensure certificates used in SMB communications are valid and properly issued. 8. Use endpoint detection and response (EDR) tools to identify suspicious activities related to SMB spoofing or lateral movement. These measures go beyond generic advice by focusing on network-level controls, monitoring, and readiness for patching specific to the nature of this certificate validation flaw.

Description

Improper certificate validation in Windows SMB allows an authorized attacker to perform spoofing over a network.

Impact

For European organizations, this vulnerability poses a risk primarily to the integrity of internal network communications that rely on SMB, a protocol widely used for file sharing and network resource access. Attackers exploiting this flaw could impersonate legitimate SMB servers or clients, potentially injecting malicious commands or data, leading to unauthorized actions or lateral movement within corporate networks. This could undermine trust in networked systems, disrupt business processes, or facilitate further attacks such as data manipulation or privilege escalation. While confidentiality and availability are not directly impacted, the integrity compromise can have cascading effects on operational reliability and security posture. Organizations with extensive Windows 11 22H2 deployments, especially in sectors with sensitive data or critical infrastructure, face increased risks. The absence of known exploits currently limits immediate threat but also underscores the importance of proactive mitigation. The medium severity rating suggests a significant but not critical threat level, warranting attention but not immediate emergency response.

CWE-295Improper Certificate Validation (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not validate, or incorrectly validates, a certificate.
Architecture and Design · Implementation
Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
Implementation
If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
TLS Cipher String (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V9.2.1 (opens in a new tab)
V1.9.2 (opens in a new tab)
V2.8.5 (opens in a new tab)
Attack patterns
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-48802 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 14 Feb 2026, 10:11 UTC

WeaknessesCWE-295

Technical details

References

Community reviews

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