CVE-2026-64919 is a stack-based buffer overflow in Microsoft Access's MDB/ACCDB file format parser, carrying a CVSS 7.8 that reflects concrete code execution risk. If you're defending an environment where Access is in use, the immediate priority is patch deployment — but understand what you're actually patching. This vulnerability is not an isolated developer error; it's symptomatic of a structural debt problem in Microsoft's legacy C++ parsing code that has persisted across Office generations. The same vulnerability class has appeared in Excel, Word, and PowerPoint's format parsers over recent years, revealing a shared architectural blast radius across the entire Office suite. When Access parses a malformed file, it's executing decades-old binary format handling code that was never rewritten in a memory-safe language — and likely never comprehensively understood, just patched when it breaks. The compound risk you should care about: Access files flow through low-trust channels — email attachments, shared drives, third-party data exchanges — handled by non-technical users with no file risk assessment framework. A stack overflow triggered by a corrupted query field or table structure can hide inside what appears to be routine business data. The patch addresses the symptom in Access, but the same binary format propagates through email gateways, document management systems, and data migration pipelines where downstream parsers may never see this update. Your defensive posture should assume this vulnerability class will recur and architect accordingly: network-level controls on MDB/ACCDB file transfers, monitoring for Access process anomalies, and explicit audit of any infrastructure that parses Access files without running Access itself.
CVE-2026-64919
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedStack-based buffer overflow in Microsoft Office Access allows an unauthorized attacker to execute code locally.
In the news
Third-party coverageSurfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisData overflows a fixed-size buffer allocated on the stack, overwriting adjacent stack memory — including saved return addresses — which is the classic route to redirecting execution into attacker-supplied code. Crafted input is all it takes. Remediation is strict length checks, safe bounded string and memory functions, and modern stack-protection mitigations.
General guidance for the stack-based buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versions= 2016all versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataThere is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.
Free. We build fixes in the order the community asks for them — and we’ll tell you the moment this one lands.
We develop and verify an original fix where the vendor hasn’t, from $4,900. Deployed to your staging first — never straight to production.
Scope it with usSee what else the community needs solved on the solutions-needed board.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-64919 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesCVE-2026-64919 is a stack-based buffer overflow in Microsoft Access's MDB/ACCDB file format parser, carrying a CVSS 7.8 that reflects concrete code execution risk. If you're defending an environment where Access is in use, the immediate priority is patch deployment — but understand what you're actually patching. This vulnerability is not an isolated developer error; it's symptomatic of a structural debt problem in Microsoft's legacy C++ parsing code that has persisted across Office generations. The same vulnerability class has appeared in Excel, Word, and PowerPoint's format parsers over recent years, revealing a shared architectural blast radius across the entire Office suite. When Access parses a malformed file, it's executing decades-old binary format handling code that was never rewritten in a memory-safe language — and likely never comprehensively understood, just patched when it breaks. The compound risk you should care about: Access files flow through low-trust channels — email attachments, shared drives, third-party data exchanges — handled by non-technical users with no file risk assessment framework. A stack overflow triggered by a corrupted query field or table structure can hide inside what appears to be routine business data. The patch addresses the symptom in Access, but the same binary format propagates through email gateways, document management systems, and data migration pipelines where downstream parsers may never see this update. Your defensive posture should assume this vulnerability class will recur and architect accordingly: network-level controls on MDB/ACCDB file transfers, monitoring for Access process anomalies, and explicit audit of any infrastructure that parses Access files without running Access itself.
Practitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-64919 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data