CVE-2026-44740
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 versions 5.9.0 and 6.0.0-alpha.1, multiple components may improperly handle crafted or malformed input, resulting in panics, infinite loops, uncontrolled recursion, or excessive resource consumption. These issues arise from insufficient validation and missing safety mechanisms such as cycle detection, recursion limits, or defensive handling of unexpected states when processing untrusted repository data and filesystem structures. This issue has been patched in versions 5.9.0 and 6.0.0-alpha.1.
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 · moderate confidenceBilly, a Go filesystem abstraction library, contains multiple vulnerabilities where insufficient input validation and missing safety mechanisms (cycle detection, recursion limits, defensive state handling) when processing untrusted repository data and filesystem structures can lead to panics, infinite loops, uncontrolled recursion, or excessive resource consumption, resulting in denial of service.
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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
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Identify Billy library version in your Go projectRun 'go list -m all | grep github.com/billy' or inspect your go.mod file for the billy version entryAffected if The billy version is listed as less than 5.9.0 or any 6.0.0 version prior to alpha.1 (e.g., 6.0.0, 6.0.0-beta.1)
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Check if Billy is a transitive dependencyRun 'go mod why github.com/billy' or 'go list -m -json github.com/billy' to see if it is pulled in by another moduleAffected if Billy appears as a dependency regardless of whether you directly import it in your code
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Identify code paths that use Billy to read filesystem dataSearch your codebase for imports of 'github.com/billy' packages (s3, mem, os, etc.) and review functions that read, list, or traverse filesystem structures using BillyAffected if Your application imports and uses Billy to process any filesystem data, especially from untrusted sources
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Determine if processed data could be untrusted or attacker-controlledReview whether Billy is used to handle data from user uploads, external repositories, network sources, or any data not directly controlled by your organizationAffected if Billy processes data from untrusted sources such as user-provided paths, external storage, or repository contents that could contain crafted filesystem structures
You are affected if Billy version is prior to 5.9.0 (or a 6.0.0 version prior to alpha.1) AND your code uses Billy to process untrusted or potentially malicious filesystem data, as the library lacks proper validation and recursion safeguards for such inputs.
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 Billy to version 5.9.0 or 6.0.0-alpha.1 which contains the patch for proper validation and safety mechanism implementation.
Billy versions 5.9.0 or 6.0.0-alpha.1
- Check the current version of Billy in use (e.g., inspect go.mod file for 'github.com/hairyhenderson/gom/v3' or similar Billy dependency)
- Run 'go get github.com/hairyhenderson/gom/[email protected]' or use the appropriate module path for the Billy library to upgrade to version 5.9.0
- Alternatively, if using the pre-release version, upgrade to '6.0.0-alpha.1'
- Run 'go mod tidy' to update dependencies
- Rebuild and test the application to verify the upgrade resolves the vulnerability
- Verify there are no regressions in filesystem operations, particularly with untrusted or malformed input
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing8.0 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 $5,472.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-44740 — 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-2026-44740 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
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- 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
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