GHSA-m6wq-39m7-9xpp

Suggest an improvement
Source
https://github.com/advisories/GHSA-m6wq-39m7-9xpp
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-m6wq-39m7-9xpp
Aliases
  • CVE-2026-62847
Published
2026-10-14T19:24:53Z
Modified
2026-10-14T19:30:07Z
Severity
  • 8.2 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H CVSS Calculator
  • 6.0 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:H CVSS Calculator
Summary
Metalama allows local code execution through DLL planting in shared temporary directories
Details

Summary

Metalama loaded and executed compile-time assemblies, auxiliary executable tools, and embedded helper assemblies from predictable temporary directories. On Linux and macOS the default cache location was the world-writable system temporary directory (Path.GetTempPath(), i.e. /tmp), and previously-generated artifacts were trusted based on the presence of a sentinel/.completed marker file rather than on any integrity verification.

A local, unprivileged user on a shared machine or CI/build agent can pre-create the deterministic cache directory structure and plant a malicious DLL together with the matching sentinel file. When a higher-privileged user (or build/service account) subsequently runs a build, Metalama finds the sentinel, skips regeneration, and loads and executes the attacker-supplied assembly inside the compiler / IDE / MSBuild process.

Affected load-and-execute paths:

  • the cache of compile-time assemblies that Metalama generates from your aspects;
  • auxiliary executable tools that Metalama extracts to a local directory and then launches;
  • embedded .NET helper assemblies that Metalama extracts to a local directory and loads into the build / IDE process.

Impact

Arbitrary code execution in the security context of the building user — i.e. a local privilege escalation across user accounts on shared POSIX systems (multi-user developer machines, CI/build agents). The attacker obtains code execution as the victim without holding the victim's privileges, and can read source/secrets, tamper with build output (supply-chain injection), or disrupt builds.

Affected configurations

  • Linux and macOS, default configuration — affected. The shipped default uses the world-writable system temp directory.
  • Windows, default configuration — not affected. The default per-user temporary directory is protected by OS ACLs, so cross-user planting is not possible.
  • The METALAMA_TEMP environment variable is a deployer-controlled override and is out of scope: pointing it at an insecure (e.g. world-writable or attacker-owned) location is a deployment misconfiguration, not a defect in the product.

Severity

CVSS v3.1: AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H = 8.2 (High) for the affected POSIX default configuration (Scope:Changed reflects the cross-user privilege escalation).

CVSS v4.0 cross-check: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:H = 6.0 (Medium), which more granularly attributes low impact to the cache itself and high impact to the subsequent build process. The honest range is therefore Medium-High depending on the scoring model and platform.

Fix

Caches and extraction directories were relocated from the world-writable system temp directory to per-user application-data locations ($XDG_CACHE_HOME / ~/.cache/Metalama on POSIX), relying on OS-enforced per-user ownership as the trust boundary. Fixed in 2026.1.19.

Weaknesses

  • CWE-377: Insecure Temporary File
  • CWE-427: Uncontrolled Search Path Element

Affected packages

  • Metalama.Framework < 2026.1.19,
  • Metalama.Tool < 2026.1.19

Internal tracking: metalama/Metalama#1650.

Database specific 
{
    "cwe_ids":  [
        "CWE-377",
        "CWE-427"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-10-14T19:24:53Z",
    "nvd_published_at":  null,
    "severity":  "MODERATE"
}
References

Affected packages

NuGet
Metalama.Framework

Package

Name
Metalama.Framework
View open source insights on deps.dev
Purl
pkg:nuget/Metalama.Framework

Affected ranges

Type
ECOSYSTEM
Events
Introduced
2026.1.0-preview
Fixed
2026.1.19

Affected versions

2026.*
2026.1.0-preview
2026.1.1-preview
2026.1.2-preview
2026.1.3-preview
2026.1.4-preview
2026.1.5-preview
2026.1.6-preview
2026.1.7-preview
2026.1.8-preview
2026.1.9-preview
2026.1.10-preview
2026.1.11-preview
2026.1.12-preview
2026.1.13-preview
2026.1.14-rc
2026.1.15-rc
2026.1.16
2026.1.17
2026.1.18

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json"
Metalama.Tool

Package

Name
Metalama.Tool
View open source insights on deps.dev
Purl
pkg:nuget/Metalama.Tool

Affected ranges

Type
ECOSYSTEM
Events
Introduced
2026.1.0-preview
Fixed
2026.1.19

Affected versions

2026.*
2026.1.0-preview
2026.1.1-preview
2026.1.2-preview
2026.1.3-preview
2026.1.4-preview
2026.1.5-preview
2026.1.6-preview
2026.1.7-preview
2026.1.8-preview
2026.1.9-preview
2026.1.10-preview
2026.1.11-preview
2026.1.12-preview
2026.1.13-preview
2026.1.14-rc
2026.1.15-rc
2026.1.16
2026.1.17
2026.1.18

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json"
Metalama.Framework

Package

Name
Metalama.Framework
View open source insights on deps.dev
Purl
pkg:nuget/Metalama.Framework

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2025.1.18

Affected versions

0.*
0.5.0-preview
0.5.1-preview
0.5.2-preview
0.5.3-preview
0.5.4-preview
0.5.5-preview
0.5.6-preview
0.5.7-preview
0.5.8-preview
0.5.9-preview
0.5.10-preview
0.5.11-preview
0.5.12-preview
0.5.13-preview
0.5.15-preview
0.5.16-preview
0.5.17-preview
0.5.18-preview
0.5.19-preview
0.5.20-preview
0.5.21-preview
0.5.22-preview
0.5.23-preview
0.5.24-preview
0.5.25-preview
0.5.26-preview
0.5.27-preview
0.5.28-preview
0.5.29-preview
0.5.30-preview
0.5.31-preview
0.5.32-preview
0.5.33-preview
0.5.34-preview
0.5.35-preview
0.5.36-preview
0.5.37-preview
0.5.38-preview
0.5.39-preview
0.5.40-preview
0.5.41-preview
0.5.42-preview
0.5.43-preview
0.5.44-preview
0.5.45-preview
0.5.46-preview
0.5.47-preview
0.5.48-preview
0.5.49-preview
0.5.50-preview
0.5.51-preview
0.5.52-preview
0.5.53-preview
0.5.54-preview
0.5.55-preview
0.5.56-preview
0.5.57-preview
0.5.58-preview
0.5.59-preview
0.5.60-preview
0.5.61-preview
0.5.62-preview
0.5.63-preview
0.5.64-preview
0.5.65-preview
0.5.66-preview
0.5.67-preview
0.5.68-preview
0.5.69-preview
0.5.70-preview
0.5.71-preview
0.5.72-preview
0.5.73-preview
0.5.74-preview
0.5.75-preview
0.5.76-preview
0.5.77-preview
0.5.78-preview
0.5.79-preview
0.5.80-preview
0.5.81-preview
0.5.82-preview
0.5.83-preview
2023.*
2023.0.101-rc
2023.0.102-rc
2023.0.103-rc
2023.0.104-rc
2023.0.105-rc
2023.0.106-rc
2023.0.107-rc
2023.0.108-rc
2023.0.109-rc
2023.0.110-rc
2023.0.111-rc
2023.0.112-rc
2023.0.113-rc
2023.0.114
2023.0.115
2023.0.116
2023.0.117
2023.0.118
2023.0.119
2023.0.120
2023.0.121
2023.1.1-preview
2023.1.2-preview
2023.1.3-preview
2023.1.4-preview
2023.1.5-preview
2023.1.6-rc
2023.1.7-rc
2023.1.8-rc
2023.1.9
2023.1.10
2023.1.11
2023.1.12
2023.2.1-preview
2023.2.2-rc
2023.2.3-rc
2023.2.4
2023.2.5
2023.3.1-preview
2023.3.2-preview
2023.3.3-preview
2023.3.4-preview
2023.3.5-rc
2023.3.6-rc
2023.3.7-rc
2023.3.8
2023.3.9
2023.3.10
2023.4.1-preview
2023.4.2-preview
2023.4.3-preview
2023.4.4-preview
2023.4.5-rc
2023.4.6
2023.4.7
2023.4.8
2023.4.9
2024.*
2024.0.1-preview
2024.0.2-preview
2024.0.3-preview
2024.0.4-rc
2024.0.5-rc
2024.0.6
2024.0.7
2024.0.8
2024.0.9
2024.0.10
2024.0.11
2024.0.12
2024.0.13
2024.0.14
2024.0.15
2024.0.16
2024.1.1-preview
2024.1.2-preview
2024.1.3-preview
2024.1.4-preview
2024.1.5-preview
2024.1.6-preview
2024.1.7-preview
2024.1.8-preview
2024.1.9-rc
2024.1.10-rc
2024.1.11-rc
2024.1.12
2024.1.13
2024.1.14
2024.1.15
2024.1.16
2024.1.17
2024.1.18
2024.1.19
2024.1.20
2024.1.21
2024.1.22
2024.1.23
2024.1.24
2024.1.25
2024.1.26
2024.1.27
2024.1.28
2024.1.29
2024.1.30
2024.2.1-preview
2024.2.2-preview
2024.2.3-preview
2024.2.4-preview
2024.2.5-preview
2024.2.6-preview
2024.2.7-preview
2024.2.8-preview
2024.2.9-preview
2024.2.10-preview
2024.2.11-preview
2024.2.12-preview
2024.2.13-rc
2024.2.14-rc
2024.2.15-rc
2024.2.16-rc
2024.2.17-rc
2024.2.18
2024.2.19
2024.2.20
2024.2.21
2024.2.22
2024.2.23
2024.2.24
2024.2.25
2024.2.26
2024.2.27
2024.2.28
2024.2.29
2024.2.30
2024.2.31
2024.2.32
2025.*
2025.0.1-preview
2025.0.2-preview
2025.0.3-preview
2025.0.4-preview
2025.0.5-preview
2025.0.6-rc
2025.0.7-rc
2025.0.8
2025.0.9
2025.0.10
2025.0.11
2025.0.12
2025.1.1-preview
2025.1.2-preview
2025.1.3-rc
2025.1.4-rc
2025.1.5
2025.1.6
2025.1.7
2025.1.8
2025.1.9
2025.1.10
2025.1.11
2025.1.12
2025.1.13
2025.1.14
2025.1.15
2025.1.16
2025.1.17

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json"
Metalama.Tool

Package

Name
Metalama.Tool
View open source insights on deps.dev
Purl
pkg:nuget/Metalama.Tool

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2025.1.18

Affected versions

0.*
0.5.77-preview
0.5.78-preview
0.5.79-preview
0.5.80-preview
0.5.81-preview
0.5.82-preview
0.5.83-preview
2023.*
2023.0.101-rc
2023.0.102-rc
2023.0.103-rc
2023.0.104-rc
2023.0.105-rc
2023.0.106-rc
2023.0.107-rc
2023.0.108-rc
2023.0.109-rc
2023.0.110-rc
2023.0.111-rc
2023.0.112-rc
2023.0.113-rc
2023.0.114
2023.0.115
2023.0.116
2023.0.117
2023.0.118
2023.0.119
2023.0.120
2023.0.121
2023.1.1-preview
2023.1.2-preview
2023.1.3-preview
2023.1.4-preview
2023.1.5-preview
2023.1.6-rc
2023.1.7-rc
2023.1.8-rc
2023.1.9
2023.1.10
2023.1.11
2023.1.12
2023.2.1-preview
2023.2.2-rc
2023.2.3-rc
2023.2.4
2023.2.5
2023.3.1-preview
2023.3.2-preview
2023.3.3-preview
2023.3.4-preview
2023.3.5-rc
2023.3.6-rc
2023.3.7-rc
2023.3.8
2023.3.9
2023.3.10
2023.4.1-preview
2023.4.2-preview
2023.4.3-preview
2023.4.4-preview
2023.4.5-rc
2023.4.6
2023.4.7
2023.4.8
2023.4.9
2024.*
2024.0.1-preview
2024.0.2-preview
2024.0.3-preview
2024.0.4-rc
2024.0.5-rc
2024.0.6
2024.0.7
2024.0.8
2024.0.9
2024.0.10
2024.0.11
2024.0.12
2024.0.13
2024.0.14
2024.0.15
2024.0.16
2024.1.1-preview
2024.1.2-preview
2024.1.3-preview
2024.1.4-preview
2024.1.5-preview
2024.1.6-preview
2024.1.7-preview
2024.1.8-preview
2024.1.9-rc
2024.1.10-rc
2024.1.11-rc
2024.1.12
2024.1.13
2024.1.14
2024.1.15
2024.1.16
2024.1.17
2024.1.18
2024.1.19
2024.1.20
2024.1.21
2024.1.22
2024.1.23
2024.1.24
2024.1.25
2024.1.26
2024.1.27
2024.1.28
2024.1.29
2024.1.30
2024.2.1-preview
2024.2.2-preview
2024.2.3-preview
2024.2.4-preview
2024.2.5-preview
2024.2.6-preview
2024.2.7-preview
2024.2.8-preview
2024.2.9-preview
2024.2.10-preview
2024.2.11-preview
2024.2.12-preview
2024.2.13-rc
2024.2.14-rc
2024.2.15-rc
2024.2.16-rc
2024.2.17-rc
2024.2.18
2024.2.19
2024.2.20
2024.2.21
2024.2.22
2024.2.23
2024.2.24
2024.2.25
2024.2.26
2024.2.27
2024.2.28
2024.2.29
2024.2.30
2024.2.31
2024.2.32
2025.*
2025.0.1-preview
2025.0.2-preview
2025.0.3-preview
2025.0.4-preview
2025.0.5-preview
2025.0.6-rc
2025.0.7-rc
2025.0.8
2025.0.9
2025.0.10
2025.0.11
2025.0.12
2025.1.1-preview
2025.1.2-preview
2025.1.3-rc
2025.1.4-rc
2025.1.5
2025.1.6
2025.1.7
2025.1.8
2025.1.9
2025.1.10
2025.1.11
2025.1.12
2025.1.13
2025.1.14
2025.1.15
2025.1.16
2025.1.17

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json"
Metalama.Tool

Package

Name
Metalama.Tool
View open source insights on deps.dev
Purl
pkg:nuget/Metalama.Tool

Affected ranges

Type
ECOSYSTEM
Events
Introduced
2026.0.0-preview
Fixed
2026.0.25

Affected versions

2026.*
2026.0.1-preview
2026.0.2-preview
2026.0.3-preview
2026.0.4-preview
2026.0.5-preview
2026.0.6-rc
2026.0.7-rc
2026.0.8-rc
2026.0.9-rc
2026.0.10-rc
2026.0.11
2026.0.12
2026.0.13
2026.0.14
2026.0.15
2026.0.16
2026.0.17
2026.0.18
2026.0.19
2026.0.20
2026.0.21
2026.0.22
2026.0.23
2026.0.24

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json"
Metalama.Framework

Package

Name
Metalama.Framework
View open source insights on deps.dev
Purl
pkg:nuget/Metalama.Framework

Affected ranges

Type
ECOSYSTEM
Events
Introduced
2026.0.0-preview
Fixed
2026.0.25

Affected versions

2026.*
2026.0.1-preview
2026.0.2-preview
2026.0.3-preview
2026.0.4-preview
2026.0.5-preview
2026.0.6-rc
2026.0.7-rc
2026.0.8-rc
2026.0.9-rc
2026.0.10-rc
2026.0.11
2026.0.12
2026.0.13
2026.0.14
2026.0.15
2026.0.16
2026.0.17
2026.0.18
2026.0.19
2026.0.20
2026.0.21
2026.0.22
2026.0.23
2026.0.24

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-m6wq-39m7-9xpp/GHSA-m6wq-39m7-9xpp.json"