CVE-2026-70571
HIGH 8.1Stack-based buffer overflow in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.
Severe if exploited (CVSS 8.1), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
1.4%chance of exploitation in 30 days · 72nd percentile
Impact if exploited
8.1CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Data snapshot:
Affected
Vendors Microsoft
Products Microsoft Exchange Server 2016 Cumulative Update 23 Microsoft Exchange Server 2019 Cumulative Update 14 Microsoft Exchange Server 2019 Cumulative Update 15 Microsoft Exchange Server Subscription Edition Rtm
Weakness (CWE)
- CWE-121: : Stack-based Buffer Overflow
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References and research data (JSON)
All CVSS metrics
- HIGH 8.1 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - HIGH 8.1 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Patches & mitigations
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70571 CVE record · microsoft · Updated 2026-10-25T18:47:00.333Z
NVD · CVE-2026-70571 · Updated 2026-10-14T04:18:35.963
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-100139 EUVD · EUVD-2026-100139