CVE-2025-21283VulnerabilityPublished 6 Feb 2025Updated 26 Feb 2026

CVE-2025-21283: Microsoft Edge (Chromium-based) · Insufficient Granularity of Address Regions Protected by Register Locks

Affects Microsoft Edge (Chromium-based)Source 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: 1.4% chance of exploitation in 30 days – higher than 73% 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/RL:O/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
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: 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.
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 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 2026-10-26.

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

AI-suggested

1. Monitor Microsoft security advisories closely and apply official patches or updates for Microsoft Edge Chromium as soon as they become available to address CVE-2025-21283. 2. Until patches are released, restrict user interaction with untrusted or suspicious web content by implementing browser security policies such as disabling JavaScript or using content filtering solutions. 3. Employ endpoint protection solutions that can detect and block suspicious browser behaviors indicative of exploitation attempts. 4. Educate users about the risks of interacting with unknown links or websites to reduce the likelihood of triggering the vulnerability. 5. Consider deploying network-level protections such as web proxies or secure web gateways that can inspect and block malicious content targeting browser vulnerabilities. 6. Use browser isolation technologies where feasible to contain potential exploitation within a sandboxed environment. 7. Regularly update all software components and dependencies related to the browser to minimize exposure to known vulnerabilities. 8. Conduct internal penetration testing and vulnerability assessments focusing on browser security to identify and remediate similar issues proactively.

Description

Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability

Impact

The vulnerability allows remote attackers to execute code within the context of the affected browser without requiring authentication or elevated privileges, posing a significant risk to user confidentiality. Successful exploitation could lead to unauthorized access to sensitive information accessible through the browser, such as cookies, session tokens, or cached data. Although integrity and availability are not directly impacted, the breach of confidentiality can facilitate further attacks like session hijacking or phishing. Organizations relying heavily on Microsoft Edge Chromium, especially in environments where users frequently interact with external web content, face increased risk of data leakage or compromise. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits once patches are released. The medium severity rating suggests that while the vulnerability is serious, it is not trivially exploitable without user interaction, somewhat limiting its scope. However, given the widespread use of Microsoft Edge globally, the potential impact on enterprise and consumer users is substantial if left unmitigated.

CWE-1222Insufficient Granularity of Address Regions Protected by Register Locks (opens in a new tab)
Variant weakness
The product defines a large address region protected from modification by the same register lock control bit. This results in a conflict between the functional requirement that some addresses need to be writable by software during operation and the security requirement that the system configuration lock bit must be set during the boot process.
Architecture and Design
The defining of protected locked registers should be reviewed or tested early in the design phase with software teams to ensure software flows are not blocked by the security locks.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Third Party Javascript Management (opens in a new tab)
Virtual Patching (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.4 (opens in a new tab)
V1.4.5 (opens in a new tab)
V1.10.1 (opens in a new tab)
Attack patterns
Exploitation of Improperly Configured or Implemented Memory Protections (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21283 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 23:33 UTC

WeaknessesCWE-1222

Technical details

References

Community reviews

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