GHSA-fcmm-42r9-mmmm: apache-airflow (CVE-2026-59242)

Apache Airflow's XCom `GET /api/v2/{...}/xcomEntries/{key}?deserialize=true` endpoint passed a string-literal payload through `BaseXCom.deserialize_value` without the `_check_forbidden_xcom_keys` g...

CVSS 5.4 MediumEPSS 0.0053 · 45th percentile

Published by the GitHub Advisory Database at 12 Aug 2026, 16:17 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
apache-airflow	PyPI	<3.3.1	3.3.1

Identifiers

GHSA-fcmm-42r9-mmmm · BIT-airflow-2026-59242 · CVE-2026-59242 · PYSEC-2026-3992

Weakness (CWE)

CWE-502

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Apache Airflow versions before 3.3.1 are vulnerable. An authenticated API user with XCom write and read access can use the XCom entries endpoint with deserialization enabled to instantiate arbitrary airflow classes on the API server. Upgrade apache-airflow to version 3.3.1 or later, which rejects reserved XCom serialization keys submitted as JSON string literals.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
5.4	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N	OSV

CISA KEV Not listed.
EPSS 0.0053, the 45th percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

12 Aug 2026, 15:35 UTC Confirmed by the CVE List
12 Aug 2026, 16:17 UTC Confirmed by NVD
31 Oct 2026, 14:08 UTC First seen by agentprime
31 Oct 2026, 14:08 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.