How severe is CVE-2017-11826?

CVE-2017-11826 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which products are affected by CVE-2017-11826?

Affected package information for CVE-2017-11826 is not yet fully mapped. Check the official advisory links for details.

How do I patch CVE-2017-11826?

No patch has shipped for CVE-2017-11826 yet — track the microsoft office compatibility pack advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2017-11826 across my infrastructure?

Inventory every microsoft office compatibility pack deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

How do I mitigate CVE-2017-11826 if there is no patch (or I can't update yet)?

Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

How does O3 Security protect against CVE-2017-11826?

O3 detects and blocks CVE-2017-11826 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Is CVE-2017-11826 actively exploited in the wild?

Yes. There are 7 known exploit references for CVE-2017-11826, including 6 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2017-11826?

CVE-2017-11826 has an EPSS (Exploit Prediction Scoring System) score of 81.5%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2017-11826 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2017-11826 (Microsoft Office Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-03-03. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-03-24. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2017-11826?

CVE-2017-11826 is classified as Buffer Overflow (CWE-119). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2017-11826?

CVE-2017-11826 affects microsoft office compatibility pack; microsoft office online server (1 version, e.g. 2016); microsoft office web apps server (2 versions, e.g. 2010, 2013); microsoft office word viewer, and 3 more product(s). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2017-11826 published, and has it been updated?

CVE-2017-11826 was published on October 13, 2017 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2022-03-03 — agencies required to remediate by 2022-03-24

CVE-2017-11826

HIGH

Microsoft Office 2010, SharePoint Enterprise Server 2010, SharePoint Server 2010, Web Applications, Office Web Apps Server 2010 and 2013, Word Viewer, Word 2007, 2010, 2013 and 2016,…

Published

Oct 13, 2017

Updated

Jun 17, 2026

Affected

0 pkgs

Patched

None yet

Exploits

7 known

EPSS Exploitation Probability

via FIRST.org ↗

81.5%probability of exploitation in next 30 days

Very High Risk100th percentile-0.17%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

Microsoft Office 2010, SharePoint Enterprise Server 2010, SharePoint Server 2010, Web Applications, Office Web Apps Server 2010 and 2013, Word Viewer, Word 2007, 2010, 2013 and 2016, Word Automation Services, and Office Online Server allow remote code execution when the software fails to properly handle objects in memory.

Affected Products

7 products · 13 configurations

Application

office compatibility packmicrosoft

all

Application

office online servermicrosoft

1 version

2016

Application

office web apps servermicrosoft

2 versions

20102013

Application

office word viewermicrosoft

all

Application

sharepoint enterprise servermicrosoft

1 version

2016

Application

sharepoint servermicrosoft

2 versions

20102013

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.