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No exploitation reported

CVE-2026-62847

No exploitation reported by the sources we read.

  • Published2026-10-30
  • WeaknessCWE-377 · CWE-427

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. Prior to 2025.1.18, 2026.0.25 and 2026.1.19, Metalama.Framework and Metalama.Tool load and execute compile-time assemblies, auxiliary executable tools and embedded helper assemblies from predictable temporary directories. On `Linux` and `macOS`, the default `Path.GetTempPath()` location is world-writable, and existing artifacts are trusted based on sentinel or `.completed` marker files rather than integrity verification. A local unprivileged user on a shared machine or CI/build agent can pre-create the deterministic directory structure and plant a malicious DLL with the matching sentinel. When a higher-privileged developer or build account subsequently builds, Metalama skips regeneration and executes the planted artifact in the compiler, IDE or MSBuild process as the building user. This permits cross-user privilege escalation, reading source and secrets, supply-chain tampering with build output, or disrupting builds. Default Windows per-user temporary directories are protected by ACLs and are not affected. Deployer-selected insecure cache locations are outside the vulnerability's scope. This issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19.

Timeline

dates in UTC
  1. 2026-10-3021:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-31 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-62847?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-62847?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-62847 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-31
  • CISA-ADPSSVC decisionnone2026-10-30
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.18.2read 2026-10-31
  • CNAweakness (CWE)CWE-377, CWE-427read 2026-10-31

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Published
2026-10-30
Last Modified
2026-10-30
NVD status
Received

Frequently asked questions

What is CVE-2026-62847?

Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. Prior to 2025.1.18, 2026.0.25 and 2026.1.19, Metalama.Framework and Metalama.Tool load and execute compile-time assemblies, auxiliary executable tools and embedded helper assemblies from predictable temporary directories. On `Linux` and `macOS`, the default `Path.GetTempPath()` location is world-writable, and existing artifacts are trusted based on sentinel or `.completed` marker files rather than integrity verification. A local unprivileged user on a shared machine or CI/build agent can pre-create the deterministic directory structure and plant a malicious DLL with the matching sentinel. When a higher-privileged developer or build account subsequently builds, Metalama skips regeneration and executes the planted artifact in the compiler, IDE or MSBuild process as the building user. This permits cross-user privilege escalation, reading source and secrets, supply-chain tampering with build output, or disrupting builds. Default Windows per-user temporary directories are protected by ACLs and are not affected. Deployer-selected insecure cache locations are outside the vulnerability's scope. This issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19.

Is CVE-2026-62847 actively exploited?

Active exploitation of CVE-2026-62847 has not been confirmed.

What is the CVSS score for CVE-2026-62847?

CVE-2026-62847 has a CVSS v3 base score of 8.2 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

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