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CVE Record

CVE-2026-44973: Billy: Path traversal vulnerabilities

Billy 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.

HighCVSS 8.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-44973 affects go-git go-billy, a Go filesystem abstraction. Versions before 5.9.0 may let crafted paths escape an intended base directory. This matters most where an application treats go-billy as isolation around sensitive files or write locations.

Executive priority

Treat as high priority where products process untrusted file paths or tenant content. Lower urgency may apply where go-billy only handles trusted internal paths, but version confirmation is still needed.

Technical view

The issue is CWE-22 path traversal caused by insufficient path sanitization and boundary enforcement across go-billy components. Applications using go-billy <5.9.0 with attacker-influenced paths may expose unintended filesystem locations. The advisory says the vulnerability is fixed in 5.9.0.

Likely exposure

Exposure is likely in Go applications that depend on go-git/go-billy before 5.9.0 and pass user-controlled or tenant-controlled paths into Billy-backed filesystem operations.

Exploitation context

The CVSS vector indicates network reachability, low attack complexity, low privileges required, and no user interaction. The provided data says KEV is false, and the sources do not state active exploitation.

Researcher notes

The advisory notes go-billy was not designed as a strong security boundary, yet inconsistent built-in behavior created isolation risk. Focus review on assumptions about base-directory containment, not only direct dependency presence.

Mitigation direction

  • Upgrade go-git/go-billy to version 5.9.0 or later.
  • Review the GitHub advisory for vendor guidance and affected implementation details.
  • Audit applications that relied on go-billy as a filesystem security boundary.
  • Add explicit path validation before Billy filesystem operations.
  • Restrict process filesystem permissions around sensitive directories.

Validation and detection

  • Check dependency manifests and SBOMs for go-git/go-billy versions below 5.9.0.
  • Identify direct and transitive uses of Billy filesystem implementations.
  • Review code paths where external input influences filesystem paths.
  • Confirm upgraded builds resolve go-billy to 5.9.0 or later.
  • Run authorized regression tests for path containment behavior.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-22: File access and web shell behavior lookup

File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-44973 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
2Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N2.85.2GitHub_M

Vulnerability scoring details

Base CVSS 3.1 score

8.1High
CVSS 3.1 vector shape for CVE-2026-44973Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
go-gitgo-billy< 5.9.0Listed
Weakness

CWE details

CWE-22

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.