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CVE-2026-49837
Out-of-Bounds Read in github.com/osrg/gobgp/v4 (CVE-2026-49837)
Summary
vulnerability in github.com/osrg/gobgp/v4 (CVE-2026-49837). Risk of unauthorized operations or information disclosure. Exploitable via ``CapLen``. Mitigation: upgrade to `4.6.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-49837** has been found in github.com/osrg/gobgp/v4.
Attackers can target a specific entry point like ``CapLen`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: ?/10.
What to do: upgrade github.com/osrg/gobgp/v4 to **4.6.0** or later.
If unsure, ask your IT team or search "github.com/osrg/gobgp/v4 CVE-2026-49837" on the vendor's site.
CVE-2026-49837 (github.com/osrg/gobgp/v4) — CWE-125 /
Attack surface: `CapLen` / `bgpd` / `BGP_CAP_FOUR_OCTET_AS_NUMBER`
Patched: `4.6.0` — 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
**out-of-bounds read** (CWE-125) exists in github.com/osrg/gobgp/v4. Attackers reach the vulnerable code path via ``CapLen`` without authentication.
📍 Affected scope
github.com/osrg/gobgp/v4 — . Attack surface: `CapLen` / `bgpd` / `BGP_CAP_FOUR_OCTET_AS_NUMBER`.
🔥 Severity
Severity: ?. Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **4.6.0**.
🛡️ 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 'github.com/osrg/gobgp/v4' .` 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
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1Identify exposure identify
grep -r 'github.com/osrg/gobgp/v4' . | 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/osrg/gobgp/v4` を grep し、稼働しているサービス・バージョンを把握する。
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6Apply patch patch
Upgrade github.com/osrg/gobgp/v4 to 4.6.0ステージング環境で 4.6.0 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。
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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
github.com/osrg/gobgp/v4
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.6.0"}]}]