Cyber Resilience

CVE-2020-17519

Apache Flink 1.11.0 – 1.11.3

CISA KEVActive ExploitationEUVD ExploitedPublic PoC
Published
05 January 2021
Modified
27 October 2025
KEV Added
23 May 2024
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.98 99.9th percentile
Risk Priority 84 floored blend · peak EPSS

Summary

CVE-2020-17519 is a high-severity Files or Directories Accessible to External Parties (CWE-552) vulnerability in Apache Flink. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked in the top 0.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Apache Flink versions 1.11.0, 1.11.1, and 1.11.2 contain a path traversal flaw in the JobManager component that exposes the local filesystem to remote reads over the REST interface. The change introduced in 1.11.0 permits requests that retrieve any file readable by the JobManager process, classified under CWE-552 with a CVSS 3.1 score of 7.5 reflecting network attack vector and high confidentiality impact without authentication requirements.

An unauthenticated attacker who can reach an exposed JobManager REST endpoint can issue crafted requests to traverse directories and exfiltrate configuration files, credentials, or other sensitive data stored on the underlying host. Exploitation is limited only by the operating-system permissions of the user account under which the JobManager executes.

Apache security advisories and the associated mailing-list announcements direct operators to upgrade immediately to Flink 1.11.3 or 1.12.0; the correction is tracked in commit b561010b0ee741543c3953306037f00d7a9f0801. Public references also include a Packet Storm entry describing directory-traversal proof-of-concept traffic targeting the affected REST endpoints.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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 commit b561010b0ee741543c3953306037f00d7a9f0801 from apache/flink:master.

CWE(s)
KEV Date Added
23 May 2024

Related Threats

MITRE ATT&CK Enterprise Techniques

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
T1039 Data from Network Shared Drive Collection
Adversaries may search network shares on computers they have compromised to find files of interest.
T1119 Automated Collection Collection
Once established within a system or network, an adversary may use automated techniques for collecting internal data.
T1530 Data from Cloud Storage Collection
Adversaries may access data from cloud storage.
T1552.001 Credentials In Files Credential Access
Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials.
T1552.004 Private Keys Credential Access
Adversaries may search for private key certificate files on compromised systems for insecurely stored credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-45627Same vendor: Apache
CVE-2023-31066Same vendor: Apache
CVE-2026-35194Same product: Apache Flink
CVE-2023-41916Same vendor: Apache
CVE-2023-50164Same vendor: Apache
CVE-2023-49198Same vendor: Apache
CVE-2025-61734Same vendor: Apache
CVE-2023-31064Same vendor: Apache
CVE-2024-27182Same vendor: Apache
CVE-2025-11371Shared CWE-552both on KEV

Affected Assets

apache
flink
1.11.0 — 1.11.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V8.4.2

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-552

Controls on authorized publication limit files and directories with nonpublic data from becoming accessible to external parties.

addresses: CWE-552

Controlling and documenting P2P file sharing prevents files and directories from being made accessible to external parties for unauthorized distribution.

addresses: CWE-552

Identifying and documenting file and directory locations allows restriction of access to external parties.

addresses: CWE-552

Protecting backup files ensures they are not accessible to external parties or unauthorized spheres.

addresses: CWE-552

Sanitizing equipment before off-site maintenance reduces the risk of files or directories containing sensitive data becoming accessible to external parties.

addresses: CWE-552

Policy restricts media access to authorized parties only, preventing exposure of resources to external or unauthorized actors.

addresses: CWE-552

Media access restrictions prevent files or directories from being accessible to external parties.

addresses: CWE-552

Employing and evaluating controls at documented alternate sites makes files and directories less likely to be accessible to external parties through physical or environmental weaknesses.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Enforcing least-privilege permissions and authorization policies directly prevents unauthorized file/directory exposure.

PR.IR-01 mostly match
prevents

Logical segmentation and access protections stop external parties from reaching files that should remain internal.

PR.DS-01 partial match
prevents

Data-at-rest protections such as encryption or ACLs reduce the impact of unintended file exposure.

PR.PS-01 partial match
prevents

Hardened configuration baselines commonly include file-system permission settings that limit external access.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

mitigates

By tracing and retrieving all copies of information stored on endpoint and portable devices, the control reduces the likelihood that files remain accessible outside the organization’s security perimeter.

mitigates

Labeling information according to its sensitivity and specifying corresponding protection measures makes it less probable that files or directories containing sensitive content will be left accessible to external parties.

mitigates

Including asset location and ownership in the inventory, combined with secure disposal procedures, decreases the chance that files or directories remain accessible to external parties after they should have been removed or restricted.

mitigates

Solid perimeters and locked external access points stop files, devices, or directories containing sensitive data from being reachable by external parties who could otherwise walk in or break in.

mitigates

Authorizing and logging the removal of storage media, disabling unused ports, and monitoring transfers limit the exposure of files or directories to external parties outside the organization’s controlled environment.

mitigates

Segregating delivery/loading zones and controlling external doors prevents external parties from reaching directories or resources that should remain inaccessible.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248579 OL 8 must restrict access to the kernel message buffer. prevents CWE-552
  • V-248597 There must be no "shosts.equiv" files on the OL 8 operating system. prevents CWE-552

References