CVE-2025-21279VulnerabilityPublished 6 Feb 2025Updated 26 Feb 2026

CVE-2025-21279: Microsoft Edge (Chromium-based) · Type Confusion

Affects Microsoft Edge (Chromium-based)Source CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 1.6% chance of exploitation in 30 days – higher than 75% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Base metrics

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

Temporal metrics

Exploit Code Maturity: Proof-of-Concept
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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.
Exploit Code Maturity: Proof-of-Concept: Proof-of-concept exploit code is available, or an attack demonstration is not practical for most systems. The code or technique is not functional in all situations and may require substantial modification by a skilled attacker.
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 6 Feb 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 2026-10-25.

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 Microsoft Edge (Chromium-based)	Affected =1.0.0.0	Fixed in–

AI-suggested

1. Immediately monitor for official patches or updates from Microsoft and apply them as soon as they become available to remediate the vulnerability. 2. Until patches are released, implement strict web content filtering and block access to untrusted or suspicious websites to reduce exposure to malicious content. 3. Employ endpoint protection solutions with behavior-based detection to identify and block exploitation attempts targeting type confusion vulnerabilities. 4. Educate users about the risks of interacting with unsolicited links or content, emphasizing caution with unknown or unexpected web pages. 5. Consider deploying application control policies that restrict execution of unauthorized code or scripts within the browser context. 6. Use network-level protections such as web proxies and intrusion prevention systems configured to detect and block exploit attempts targeting browser vulnerabilities. 7. Regularly audit and update browser versions across the organization to minimize the attack surface and ensure known vulnerabilities are patched promptly. 8. For high-risk environments, consider disabling or limiting the use of the affected Edge version until a secure update is available.

Description

Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability

Impact

The primary impact of CVE-2025-21279 is the potential for remote code execution within the context of the user running Microsoft Edge, leading to unauthorized access to sensitive information. Since the vulnerability affects confidentiality with high impact, attackers could exfiltrate data or perform actions that compromise user privacy. The lack of impact on integrity and availability means the system's data and operations remain unaltered and operational, but the confidentiality breach alone can have severe consequences, especially for organizations handling sensitive or regulated data. The requirement for user interaction (e.g., visiting a malicious website) limits the attack vector but does not eliminate risk, as phishing and social engineering remain effective. Organizations worldwide using the affected Edge version are at risk, particularly those with high-value targets such as government agencies, financial institutions, and enterprises with sensitive intellectual property. The absence of known exploits in the wild provides a window for proactive mitigation, but the lack of patches necessitates caution.

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21279 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 23:32 UTC

WeaknessesCWE-843

Technical details

References

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