Memory corruption
Heap-based buffer overflow in Windows Installer allows an authorized attacker to elevate privileges locally
At a glance
~0.3% estimated chance of attack in 30 days. Exploitation not confirmed.
Low rather than Medium: UK relevance is 40 of 100, little UK-specific signal so far.
Briefing
There is no written leader briefing for this story yet. These questions come from the facts we hold.
Questions to ask IT
- Are we affected by CVE-2026-71339, and which of our systems would be?
- If it is not yet patched, what mitigation is in place, and will the fix be done by 10 Dec?
Next steps
- Confirm whether this affects systems or suppliers in your estate
Vulnerability facts
Full CVE detail CVE-2026-71339- 6.7 · MediumExploitable only with local access and an administrator-level account, and no one has to click or open anything. High impact on confidentiality, integrity and availability.CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- Not listed
- ~0.3% estimated chance of attack in 30 days
No technical write-up beyond these facts and the summary below yet.
Next steps
- Review the advisory against your asset inventory and patch cadence
Summary
- Updated an acknowledgement. This is an informational change only.
- CVE-2026-71339 has an estimated ~0.3% chance of attack in 30 days (28.7th percentile) as of 2026-11-10 — probability signal, not confirmed exploitation
Read the original reportMicrosoft Security Update Guide RSS(opens in a new tab)
Pulse
Last change 46m ago · Next recheck 11 Nov 2026, 22:09 UK time
- Story10 Nov 2026, 22:09 UK time · 46m ago
Linked reporting from Microsoft Security Update Guide RSS (vendor psirt).
Read source (Microsoft Security Update Guide RSS)
1 entry so far. The timeline chart appears once this story has more history.
Sources
CVE-2026-71339 Windows Installer Elevation of Privilege Vulnerability
How we know
Statements extracted from sources. Higher confidence means stronger corroboration.
- ClaimedHeadline60% confidence
Heap-based buffer overflow in Windows Installer allows an authorised attacker to elevate privileges locally
- ProbableSummary fact75% confidence
Updated an acknowledgement. This is an informational change only.
- ConfirmedCVE identifier95% confidence
Event involves CVE-2026-71339
- ConfirmedEstimated attack likelihood95% confidence
CVE-2026-71339 has an estimated ~0.3% chance of attack in 30 days (28.7th percentile) as of 2026-11-10 — probability signal, not confirmed exploitation