Microsoft
Improperly implemented security check for standard in Microsoft PowerShell allows an unauthorized attacker to bypass a security feature over a network
At a glance
~0.6% 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
- Do not treat uncorroborated claims as confirmed breaches.
Questions to ask IT
- Do we run Microsoft PowerShell, and which versions?
- If it is not yet patched, what mitigation is in place, and will the fix be done by 30 Nov?
Next steps
- Confirm whether this affects systems or suppliers in your estate
Vulnerability facts
Full CVE detail CVE-2026-96303- 6.5 · MediumExploitable over the network without any account, but only if a user takes an action, such as opening a file or link. High impact on integrity.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- Not listed
- ~0.7% 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
- Corrected Fixed Build Number and Download links in the Security Updates table. This is an informational change only.
- CVE-2026-96303 has an estimated ~0.6% chance of attack in 30 days (47.6th percentile) as of 2026-10-22 — probability signal, not confirmed exploitation
Read the original reportMicrosoft Security Update Guide RSS(opens in a new tab)
Products and services involved
- Microsoft PowerShell93% match confidence · CVE-2026-96303
Pulse
Last checked 31 Oct · Recheck overdue since 1 Nov 2026, 07:38 UK time
- Story22 Oct 2026, 23:42 UK time · 22 Oct
Linked reporting from Microsoft Security Update Guide RSS (vendor psirt).
Read source (Microsoft Security Update Guide RSS) - Update27 Oct 2026, 08:07 UK time · 27 Oct
Attack-likelihood ranking among CVEs rose from the 47.6% to 52.6%.
- Update31 Oct 2026, 07:38 UK time · 31 Oct
held at 0.6%; ranking metadata was updated.
3 entries so far. The timeline chart appears once this story has more history.
Sources
CVE-2026-96303 Microsoft PowerShell Security Feature Bypass Vulnerability
How we know
Statements extracted from sources. Higher confidence means stronger corroboration.
- ClaimedHeadline60% confidence
Improperly implemented security check for standard in Microsoft PowerShell allows an unauthorised attacker to bypass a security feature over a network
- ProbableSummary fact75% confidence
Corrected Fixed Build Number and Download links in the Security Updates table. This is an informational change only.
- ConfirmedCVE identifier95% confidence
Event involves CVE-2026-96303
- ConfirmedEstimated attack likelihood95% confidence
CVE-2026-96303 has an estimated ~0.6% chance of attack in 30 days (47.6th percentile) as of 2026-10-22 — probability signal, not confirmed exploitation