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CVE-2023-45139
XXE (XML External Entity) in fonttools (CVE-2023-45139)
Summary
vulnerability in fonttools (CVE-2023-45139). Confidential information can be exposed externally. Mitigation: upgrade to `4.43.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2023-45139** has been found in fonttools.
Confidential information can be exposed externally. CVSS score: ?/10.
What to do: upgrade fonttools to **4.43.0** or later.
If unsure, ask your IT team or search "fonttools CVE-2023-45139" on the vendor's site.
CVE-2023-45139 (fonttools) — CWE-611 /
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: `4.43.0` — 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
**A vulnerability** (CWE-611) exists in fonttools.
📍 Affected scope
fonttools — .
🔥 Severity
Severity: ?. Confidential information can be exposed externally
🔧 How to fix
Update to **4.43.0**.
🛡️ 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 'fonttools' .` 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 'fonttools' . | 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 `fonttools` 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 fonttools to 4.43.0ステージング環境で 4.43.0 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
PyPI
fonttools
[{"type":"ECOSYSTEM","events":[{"introduced":"4.28.2"},{"fixed":"4.43.0"}]}]
References
- advisory https://nvd.nist.gov/vuln/detail/CVE-2023-45139
- advisory https://github.com/advisories/GHSA-6673-4983-2vx5
- package https://github.com/fonttools/fonttools
- package https://pypi.org/project/fonttools
- web https://github.com/fonttools/fonttools/security/advisories/GHSA-6673-4983-2vx5
- web https://github.com/fonttools/fonttools/commit/9f61271dc1ca82ed91f529b130fe5dc5c9bf1f4c
- web https://github.com/fonttools/fonttools/releases/tag/4.43.0
- web https://lists.fedoraproject.org/archives/list/[email protected]/message/VY63B4SGY4QOQGUXMECRGD6K3YT3GJ75
- web http://www.openwall.com/lists/oss-security/2024/03/08/2
- web http://www.openwall.com/lists/oss-security/2024/03/09/1