Unsafe Deserialization in apache-airflow (CVE-2026-42359)
Summary
Vulnerability in apache-airflow (CVE-2026-42359). Successful exploitation can lead to full system takeover. Exploitable via PATCH /api/v2/xcomEntries/{key}. Mitigation: upgrade to 3.2.2 or later.
Original description
The description as published by the source.
A bug in Apache Airflow's XCom PATCH endpoint PATCH /api/v2/xcomEntries/{key} allowed an authenticated UI/API user with XCom write permission on a Dag to set XCom entries under reserved key names (e.g. return_value) that the matching POST endpoint already validated against FORBIDDEN_XCOM_KEYS. The endpoint also accepted serialized payload shapes the triggerer's deserializer treats as code; combined, this allowed RCE on the triggerer when the affected task next deferred. Affects deployments where untrusted users have XCom write permission on Dags that defer to the triggerer. This is a fix-bypass of CVE-2026-33858: PR #64148 added the FORBIDDEN_XCOM_KEYS validator only on the POST/set path; the PATCH path was not covered. Users who already upgraded for CVE-2026-33858 should additionally upgrade to apache-airflow 3.2.2 or later to cover the PATCH-path bypass.
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-2026-42359 has been found in apache-airflow.
Attackers can target a specific entry point like PATCH /api/v2/xcomEntries/{key} over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade apache-airflow to 3.2.2 or later.
If unsure, ask your IT team or search "apache-airflow CVE-2026-42359" on the vendor's site.
CVE-2026-42359 (apache-airflow) — CWE-502 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: PATCH /api/v2/xcomEntries/{key} / return_value / FORBIDDEN_XCOM_KEYS
Patched: 3.2.2 — 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.
Unsafe deserialization (CWE-502) exists in apache-airflow. Attackers reach the vulnerable code path via PATCH /api/v2/xcomEntries/{key}.
Check the vendor advisory for the affected versions of apache-airflow. Attack surface: PATCH /api/v2/xcomEntries/{key} / return_value / FORBIDDEN_XCOM_KEYS.
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.
Update to 3.2.2.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual PATCH /api/v2/xcomEntries/{key} requests with malformed payloads or SQL meta-characters. Run grep -r 'apache-airflow' . 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
-
1Identify exposure identify
grep -r 'apache-airflow' . | 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
apache-airflowを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'PATCH /api/v2/xcomEntries/{key}' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
PATCH /api/v2/xcomEntries/{key}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。 -
3Apply patch patch
Upgrade apache-airflow to 3.2.2ステージング環境で 3.2.2 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 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against PATCH /api/v2/xcomEntries/{key} 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
References
- advisory nvd.nist.gov
- advisory lists.apache.org
- advisory github.com
- package github.com
- patch github.com
- web github.com
- web cve.org
- web github.com
- web pypi.python.org