CVE-2026-44973
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 · uneditedBilly is an interface filesystem abstraction for Go. Prior to 5.9.0, multiple path traversal issues exist across different components of go-billy. Insufficient path sanitization and boundary enforcement may allow crafted paths (e.g., using ..) to escape intended base directories. While go-billy was not originally designed to provide a strong security boundary, some of these issues were inconsistent across some of the built-in implementations. This results in scenarios where applications relying on go-billy for some level of isolation may inadvertently expose access to unintended filesystem locations. This vulnerability is fixed in 5.9.0.
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 analysis · high confidenceBilly (go-billy) versions before 5.9.0 contain multiple path traversal vulnerabilities due to insufficient path sanitization and inconsistent boundary enforcement across built-in filesystem implementations. Attackers can use path traversal sequences (e.g., '../') to escape intended base directories and access filesystem locations outside the intended scope.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify go-billy as a dependencySearch your project for go-billy imports (e.g., 'gopkg.in/billy.v*') in go.mod, go.sum, or source filesAffected if go-billy is present as a dependency
-
Check the installed versionRun 'go list -m all | grep billy' or inspect go.mod to find the exact version of go-billyAffected if version is below 5.9.0 or cannot be determined to be 5.9.0 or later
-
Determine if the application relies on go-billy for security boundariesReview code for uses of go-billy's filesystem where isolation is intended (e.g., restricting file access to a base directory)Affected if the application uses go-billy to enforce directory isolation or access controls
-
Check if user-controlled input flows to filesystem operationsSearch for patterns where user input (HTTP parameters, API payloads, CLI arguments) is passed to billy filesystem methods like Open, ReadDir, or WriteAffected if user input reaches go-billy filesystem operations without additional sanitization beyond what go-billy provides
If go-billy is present with a version below 5.9.0 and the application relies on its directory isolation for security or processes user input through it, the environment is likely affected.
Generated from the published advisory. Verify against your own configuration.
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.
dbcve · scopedUpgrade go-billy to version 5.9.0 or later to obtain the path sanitization fixes, and audit existing code that relies on Billy for filesystem isolation to ensure proper usage patterns.
billy v5.9.0
- 1. Locate the go-billy dependency in your project's go.mod file
- 2. Run 'go get github.com/go-billy/[email protected]' to upgrade to the fixed version
- 3. Run 'go mod tidy' to update the dependency tree
- 4. Rebuild and test your application to verify the upgrade doesn't break existing functionality
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,160.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-44973 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-44973 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
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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