Affects the Windows DHCP Client — a widely deployed OS component. Remote/adjacent privilege escalation on many endpoints risks enterprise-wide compromise and operational disruption.
CVE-2026-88240
Heap overflow in Windows DHCP Client enables adjacent-network privilege escalation.
Is CVE-2026-88240 being exploited?
Not confirmed. CVE-2026-88240 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.44% probability of exploitation in the next 30 days.
How severe is CVE-2026-88240?
CVE-2026-88240 is rated High with a CVSS score of 8.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-88240?
Yes. A fix has been recorded for CVE-2026-88240. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-88240 affect?
CVE-2026-88240 affects Microsoft Windows DHCP Client, Windows (supported client & server versions). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-88240?
Apply Microsoft security updates immediately; block untrusted DHCP sources
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Heap-based buffer overflow in DHCP client lets an attacker on an adjacent network escalate privileges to SYSTEM via crafted DHCP responses.
Immediate action required
- affected>= 10.0.14393.0 and < 10.0.14393.9688
- affected>= 10.0.17763.0 and < 10.0.17763.9487
- affected>= 10.0.19044.0 and < 10.0.19044.7846
- affected>= 10.0.19045.0 and < 10.0.19045.7846
- affected>= 10.0.22631.0 and < 10.0.22631.7711
- affected>= 10.0.22631.0 and < 10.0.22631.7711
- affected>= 10.0.26100.0 and < 10.0.26100.9974
- affected>= 10.0.26200.0 and < 10.0.26200.9974
- affected>= 10.0.28000.0 and < 10.0.28000.3501
- affected>= 10.0.26300.0 and < 10.0.26300.9974
- affected>= 10.0.14393.0 and < 10.0.14393.9688
- affected>= 10.0.14393.0 and < 10.0.14393.9688
- affected>= 10.0.17763.0 and < 10.0.17763.9487
- affected>= 10.0.17763.0 and < 10.0.17763.9487
- affected>= 10.0.20348.0 and < 10.0.20348.5870
- affected>= 10.0.26100.0 and < 10.0.26100.33822
- affected>= 10.0.26100.0 and < 10.0.26100.33822
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
cisa ssvc
- exploitation
- none
- automatable
- no
- technical impact
- total
Assessed by CISA 11 Nov 2026 (SSVC 2.0.3).
timeline
- 10 Nov 2026Published
- 11 Nov 2026CISA SSVC assessment: exploitation none · 1 day later
- 11 Nov 2026CVE record last updated · same day later
- 12 Nov 2026Analysed by vulneraibility.com · 1 day later
- Patchmsrc.microsoft.com /update-guide/vulnerability/CVE-2026-88240
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.