Categories
CVE-2026-46354 critical CVSS 9.1

Vulnerability in github.com/coder/coder/v2 (CVE-2026-46354)

Summary

Vulnerability in github.com/coder/coder/v2 (CVE-2026-46354). Confidential information can be exposed externally. Exploitable via POST /api/v2/workspaceagents/azure-instance-identity. Mitigation: upgrade to 2.24.5 or later.

Original description

The description as published by the source.

Coder allows organizations to provision remote development environments via Terraform. In versions prior tp 2.24.5, 2.29.13, 2.30.8, 2.31.12, 2.32.2, and 2.33.3, azureidentity.Validate() verifies that the PKCS#7 signer certificate chains to a trusted Azure CA but never verifies the PKCS#7 signature itself. An attacker can embed a legitimate Azure certificate alongside arbitrary content e.g. {"vmId":""} and the forged vmId will be accepted returning the victim workspace agent's session token. No authentication is required. The attacker only needs to know a target VM's vmId which is a UUIDv4. That's a practical limitation which would typically require prior access to be exploited. Versions 2.24.5, 2.29.13, 2.30.8, 2.31.12, 2.32.2, and 2.33.3 patch the issue. As a workaround, reconfigure any Azure templates to use token authentication rather than azure-instance-identity.

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-46354 has been found in github.com/coder/coder/v2.
Attackers can target a specific entry point like POST /api/v2/workspaceagents/azure-instance-identity over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: upgrade github.com/coder/coder/v2 to 2.24.5 or later.
If unsure, ask your IT team or search "github.com/coder/coder/v2 CVE-2026-46354" on the vendor's site.

CVE-2026-46354 (github.com/coder/coder/v2) — CWE-347 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /api/v2/workspaceagents/azure-instance-identity / GET /workspaceagents/me/gitsshkey / GET /workspaceagents/me/external-auth / vmId
Patched: 2.24.5 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-347) exists in github.com/coder/coder/v2. Attackers reach the vulnerable code path via POST /api/v2/workspaceagents/azure-instance-identity without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/coder/coder/v2. Attack surface: POST /api/v2/workspaceagents/azure-instance-identity / GET /workspaceagents/me/gitsshkey / GET /workspaceagents/me/external-auth / vmId.

🔥 Severity

Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 2.24.5.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual POST /api/v2/workspaceagents/azure-instance-identity requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/coder/coder/v2' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    grep -r 'github.com/coder/coder/v2' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/coder/coder/v2 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect
    grep 'POST /api/v2/workspaceagents/azure-instance-identity' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /api/v2/workspaceagents/azure-instance-identity への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch
    Upgrade github.com/coder/coder/v2 to 2.24.5

    ステージング環境で 2.24.5 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify
    Replay attack against POST /api/v2/workspaceagents/azure-instance-identity on staging to confirm patch closes the vector

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

go github.com/coder/coder/v2
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.24.5"}]}]
go github.com/coder/coder
[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"0.27.3"}]}]

References

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