Microsoft
Inefficient algorithmic complexity in .NET allows an unauthorized attacker to deny service over a network
At a glance
Low rather than Medium: UK relevance is 40 of 100, little UK-specific signal so far.
Briefing
- Do not treat uncorroborated claims as confirmed breaches.
Questions to ask IT
- Do we run Microsoft .net, and which versions?
- If it is not yet patched, what mitigation is in place, and will the fix be done by 3 Dec?
Next steps
- Confirm whether this affects systems or suppliers in your estate
Vulnerability facts
Full CVE detail CVE-2026-69651- 7.5 · HighExploitable over the network without any account, and no one has to click or open anything. High impact on availability.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Not listed
- ~1.3% estimated chance of attack in 30 days
- Not linked from the CVE record
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 the Security Updates table to add KB article links for.NET 11.0. This is an informational change only; the fixed builds are unchanged.
Read the original reportMicrosoft Security Update Guide RSS(opens in a new tab)
Products and services involved
- Microsoft .net84% match confidence · CVE-2026-69651
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Pulse
Last checked 5d ago · Recheck overdue since 4 Nov 2026, 07:38 UK time
- Story15 Oct 2026, 22:43 UK time · 15 Oct
Linked reporting from Microsoft Security Update Guide RSS (vendor psirt).
Read source (Microsoft Security Update Guide RSS) - Signal24 Oct 2026, 17:09 UK time · 24 Oct
in the next 30 days first recorded at 1.1% (lower likelihood signal, not confirmed exploitation).
- Signal3 Nov 2026, 07:38 UK time · 5d ago
in the next 30 days first recorded at 1.3% (lower likelihood signal, not confirmed exploitation).
3 entries so far. The timeline chart appears once this story has more history.
Sources
CVE-2026-69651 .NET Denial of Service Vulnerability
How we know
Statements extracted from sources. Higher confidence means stronger corroboration.
- ClaimedHeadline60% confidence
Inefficient algorithmic complexity in.NET allows an unauthorised attacker to deny service over a network
- ProbableSummary fact75% confidence
Updated the Security Updates table to add KB article links for.NET 11.0. This is an informational change only; the fixed builds are unchanged.
- ConfirmedCVE identifier95% confidence
Event involves CVE-2026-69651