CVE-2015-2502 is a memory corruption vulnerability in Microsoft Internet Explorer. CISA added it to the Known Exploited Vulnerabilities catalogue on 13 April 2022, which means attackers have used it in real attacks. Microsoft Internet Explorer contains a memory corruption vulnerability that allows an attacker to execute code or cause a denial-of-service (DoS).
What this vulnerability means in practice
Memory corruption in a browser is dangerous because it can turn ordinary web content into code execution or a crash. In Internet Explorer, that means a malicious page or injected content can potentially break out of the browser’s normal safety boundaries and run attacker-controlled code on the victim system.
For a vulnerability with known real-world exploitation, the practical question is not only what the bug class is, but whether the affected browser still exists anywhere in the environment, including legacy hosts, embedded systems, kiosk images, or compatibility modes. For authoritative record details, use the CVE Program and the NIST National Vulnerability Database.
Why browser memory corruption is high impact
Browser memory corruption is especially serious because browsers sit at the boundary between untrusted internet content and local system resources. A successful exploit can lead to arbitrary code execution, which is often the first step toward malware installation, credential theft, lateral movement, or persistent access.
Even when the immediate effect is only a crash, a denial-of-service event can still matter in operational terms if the browser is part of a business workflow, a call-center workstation, or a legacy application estate. In other words, the same defect can create both security and availability consequences depending on how the browser is used.
This is why browser flaws are often treated as exposure issues, not just software bugs. If the vulnerable product is still deployed, the attack surface includes the browser itself, the user’s browsing behavior, and any higher-privilege integrations that the browser can reach.
How organisations determine exposure
The first step is simple but often missed: confirm where Microsoft Internet Explorer still exists. That includes desktop fleets, virtual desktops, terminal servers, unmanaged legacy endpoints, and applications that invoke IE components under the hood.
Exposure review should also check whether the browser is reachable from the internet, whether users can browse arbitrary external sites, and whether compensating controls such as application allowlisting or restricted browsing are in place. Vendor advisories and the CISA Known Exploited Vulnerabilities catalogue are the right sources for patch and exploitation status, while internal asset inventory shows whether the issue is actually present.
For vulnerability prioritisation and remediation workflow design, see NHIMG’s Vulnerability Management Guide, which covers asset scope, KEV-based prioritisation, verification, and remediation tracking.
Remediation, detection, and identity impact
Where a patch is available, remediation should be treated as urgent because exploitation can already be in the wild. If patching cannot happen immediately, organisations need compensating controls such as restricting access to untrusted sites, reducing browser privilege, tightening egress control, and isolating legacy browsing paths from sensitive accounts and data.
Detection should look for exploit activity, unusual browser crashes, suspicious child processes, script engines launching unexpected binaries, and post-exploitation artifacts such as new persistence mechanisms or altered security settings. After patching, review whether the endpoint shows signs that the exploit already succeeded before remediation.
If exploitation is suspected, rotate any credentials, tokens, or sessions that may have been exposed on the affected endpoint. A browser compromise often becomes an identity problem quickly, because the attacker may steal authentication material from the user context, web sessions, or cached browser data.
Risk and Threat Considerations
This vulnerability matters because it can convert a simple visit to a hostile page into code execution on a trusted endpoint. When the browser is used in privileged or enterprise contexts, the attacker may gain a foothold that outlives the browser session itself.
Failure mechanism: The exploit abuses memory corruption to seize execution flow, then uses the compromised browser process or user context to reach local data, sessions, or follow-on attack paths.
Impact: The result can include malware deployment, data theft, credential compromise, persistence, or denial of service on systems that still depend on Internet Explorer.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
CIS Controls v8, NIST SP 800-53 Rev 5 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | Exploit-known browser flaws need fast discovery and remediation. |
| Recommendation — Prioritise, validate, and remediate the affected browser exposure quickly. | ||
| NIST SP 800-53 Rev 5 | SI-2 — Flaw Remediation | This CVE is a software flaw that requires timely remediation and verification. |
| SI-4 — System Monitoring | Active exploitation makes endpoint and browser detection signals materially important. | |
| Recommendation — Track, remediate, and verify the vulnerability under formal flaw-remediation controls. Monitor endpoints for exploit indicators and post-compromise behavior. | ||
| NIST CSF 2.0 | ID.AM-01 — Physical devices and systems within the organization are inventoried | Exposure depends on finding where Internet Explorer still exists in the fleet. |
| PR.IR-01 — Networks, systems, devices, applications and data are protected from malicious code | Browser memory corruption can deliver malicious code through untrusted web content. | |
| Recommendation — Inventory affected endpoints and browser instances before planning remediation. Reduce malicious-code exposure on legacy browsing paths and affected systems. | ||
Practitioner Guidance
Why practitioners should care: Legacy browser exposure is often hidden inside application compatibility, so the risk can persist even after an organisation believes it has moved on from Internet Explorer. Treat any remaining use as a separately governed exception, not a harmless convenience.
What to watch for: Prioritise any endpoint that can still open external content, especially if it also handles email, finance, admin work, or authenticated business portals. Those systems turn a browser exploit into a broader enterprise incident much faster.