CVE-2020-17519 — Apache Flink Improper Access Control Vulnerability

A change introduced in Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the JobManager through the REST interface of the JobManager process. Access is restricted to files accessible by the JobManager proc

01What is this vulnerability?

A change introduced in Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the JobManager through the REST interface of the JobManager process. Access is restricted to files accessible by the JobManager process. All users should upgrade to Flink 1.11.3 or 1.12.0 if their Flink instance(s) are exposed. The issue was fixed in…

02Affected products

Vendor	Product	Versions
Apache Software Foundation	Apache Flink	Apache Flink 1.11.0 to 1.11.2

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2024-05-23. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2021-01-05T11:40:14.000Z
• Last modified: 2025-10-21T23:35:30.697Z
• Added to CISA KEV: 2024-05-23
• BOD 22-01 due: 2024-06-13

09References

• lists.apache.org — https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038…
• lists.apache.org — https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038…
• lists.apache.org — https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038…
• lists.apache.org — https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038…
• www.openwall.com — http://www.openwall.com/lists/oss-security/2021/01/05/2
• lists.apache.org — https://lists.apache.org/thread.html/r28f17e564950d663e68cc6fe75756012dda62ac623…
• packetstormsecurity.com — http://packetstormsecurity.com/files/160849/Apache-Flink-1.11.0-Arbitrary-File-R…
• lists.apache.org — https://lists.apache.org/thread.html/r2fc60b30557e4a537c2a6293023049bd1c49fd92b5…
• lists.apache.org — https://lists.apache.org/thread.html/r4e1b72bfa789ea5bc20b8afe56119200ed25bdab0e…
• lists.apache.org — https://lists.apache.org/thread.html/r0a433be10676f4fe97ca423d08f914e0ead341c901…
• lists.apache.org — https://lists.apache.org/thread.html/r88b55f3ebf1f8f4e1cc61f030252aaef4b77060b56…
• lists.apache.org — https://lists.apache.org/thread.html/r88f427865fb6aa6e6378efe07632a1906b430365e1…
• lists.apache.org — https://lists.apache.org/thread.html/ra8c96bf3ccb4e491f9ce87ba35f134b4449beb2a38…
• lists.apache.org — https://lists.apache.org/thread.html/r229167538863518738e02f4c1c5a8bb34c1d45dadc…
• lists.apache.org — https://lists.apache.org/thread.html/r90890afea72a9571d666820b2fe5942a0a5f86be40…
• lists.apache.org — https://lists.apache.org/thread.html/r1125f3044a0946d1e7e6f125a6170b58d413ebd4a9…
• lists.apache.org — https://lists.apache.org/thread.html/r26fcdd4fe288323006253437ebc4dd6fdfadfb5e93…