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CVE-2026-27140
high
CVSS 8.8
Vulnerability in toolchain (CVE-2026-27140)
Summary
vulnerability in toolchain (CVE-2026-27140). Successful exploitation can lead to full system takeover. Mitigation: upgrade to `1.25.9, 1.26.2` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-27140** has been found in toolchain.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade toolchain to **1.25.9, 1.26.2** or later.
If unsure, ask your IT team or search "toolchain CVE-2026-27140" on the vendor's site.
CVE-2026-27140 (toolchain) — CWE-641 / CVSS v3 8.8
Attack vector: remote (network-reachable) / unauthenticated
Patched: `1.25.9, 1.26.2` — 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-641) exists in toolchain.
📍 Affected scope
toolchain — .
🔥 Severity
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover
🔧 How to fix
Update to **1.25.9, 1.26.2**.
🛡️ 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 request patterns matching this CVE's known IOCs. Run `grep -r 'toolchain' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'toolchain' . | 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 `toolchain` を grep し、稼働しているサービス・バージョンを把握する。
-
6Apply patch patch
Upgrade toolchain to 1.25.9, 1.26.2ステージング環境で 1.25.9, 1.26.2 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 3 で見つけた異常検知の続報チェックを含めること。
-
7Post-deployment verification verify
Confirm patched version is live in production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 3 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
toolchain
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.25.9"},{"introduced":"1.26.0-0"},{"fixed":"1.26.2"}]}]
References
- web https://go.dev/cl/763768
- web https://go.dev/issue/78335
- web https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU
- web https://nvd.nist.gov/vuln/detail/CVE-2026-27140
- web https://pkg.go.dev/vuln/GO-2026-4871
- web https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27140.json
- web https://bugzilla.redhat.com/show_bug.cgi?id=2456341
- web https://access.redhat.com/security/cve/CVE-2026-27140
- web https://access.redhat.com/errata/RHSA-2026:25182
- web https://access.redhat.com/errata/RHSA-2026:23246
- web https://access.redhat.com/errata/RHSA-2026:16698
- web https://access.redhat.com/errata/RHSA-2026:16697
- web https://access.redhat.com/errata/RHSA-2026:16694
- web https://access.redhat.com/errata/RHSA-2026:16498
- web https://access.redhat.com/errata/RHSA-2026:16497
- web https://access.redhat.com/errata/RHSA-2026:16494
- web https://access.redhat.com/errata/RHSA-2026:16024
- web https://access.redhat.com/errata/RHSA-2026:16021
- web https://access.redhat.com/errata/RHSA-2026:10704
- web https://access.redhat.com/errata/RHSA-2026:10219
- web https://access.redhat.com/errata/RHSA-2026:10217
- web https://github.com/advisories/GHSA-5w89-2c2x-6x66
- web https://access.redhat.com/errata/RHSA-2026:34099
- web https://access.redhat.com/errata/RHSA-2026:56854
- web https://access.redhat.com/errata/RHSA-2026:57408
- web https://access.redhat.com/errata/RHSA-2026:57545