CVE-2026-62735: Windows HTTP.sys Elevation of Privilege Vulnerability

highCVSS 7.8CVE-2026-62735

Heap-based buffer overflow in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.

CSIRTS triage

vendor: Microsoft product: Windows HTTP.sys Privilege escalation Memory corruption

What: Heap-based buffer overflow in HTTP.sys enables local privilege escalation.
Who is affected: Authorized local attackers on Windows systems running HTTP.sys.
Urgency: High priority; CVSS 7.8 heap overflow with privilege escalation requires immediate patching.
Action: Apply Microsoft security update for Windows HTTP.sys immediately.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.8
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62735

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-627350.38% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 31% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-62735	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

critical[NEW] [critical] Microsoft Windows Products: Multiple vulnerabilitiescert-bund
unknownexploitedNCSC-2026-0284 [1.00] [M/H] Vulnerabilities patched in Microsoft Windowsncsc-nl
highCVE-2026-62735: Heap-based buffer overflow in Windows HTTP.sys allows an authorized attacker to elevate privil…nvd

Recent advisories for Windows HTTP.sys Elevation

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-62811: Heap-based buffer overflow in Windows HTTP.sys allows an authorized attacker to elevate privil…nvd · 2026-08-11
highCVE-2026-62753: Heap-based buffer overflow in Windows HTTP.sys allows an authorized attacker to elevate privil…nvd · 2026-08-11
highCVE-2026-62741: Integer underflow (wrap or wraparound) in Windows HTTP.sys allows an authorized attacker to el…nvd · 2026-08-11
highCVE-2026-62739: Heap-based buffer overflow in Windows HTTP.sys allows an authorized attacker to elevate privil…nvd · 2026-08-11
highCVE-2026-62735: Heap-based buffer overflow in Windows HTTP.sys allows an authorized attacker to elevate privil…nvd · 2026-08-11
highCVE-2026-61937: Integer overflow or wraparound in Windows HTTP.sys allows an authorized attacker to elevate pr…nvd · 2026-08-11