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CVE-2020-17518

Apache Flink directory traversal attack: remote file writing through the REST API

Exploitation likely. EPSS gives it a 49% chance of exploitation in the next 30 days. Fixed in 1.11.3.

CVSS 3.17.5HighEPSS percentile99th49% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix1.11.3Upgrade to this build

Published Updated Sources: CVE.org, NVD, GitHub

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Apache Software Foundation Apache FlinkAffected: Apache Flink 1.5.1 to 1.11.2Upgrade to: not statedStated by: CVE record
  • Maven org.apache.flink:flink-runtimeAffected: ≥ 1.5.1, < 1.11.3Upgrade to: 1.11.3Stated by: GitHub advisory

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free Nuclei and OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Discuss checks for your systems with a specialist. Scope is agreed before testing.

What it is

From the CVE record

Apache Flink 1.5.1 introduced a REST handler that allows you to write an uploaded file to an arbitrary location on the local file system, through a maliciously modified HTTP HEADER. The files can be written to any location accessible by Flink 1.5.1. 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 a5264a6f41524afe8ceadf1d8ddc8c80f323ebc4 from apache/flink:master.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS99th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

49% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

10 events over 2112 days, from the signal feeds we watch.

  1. EPSS band changehigh → moderateepss band change
  2. OpenVAS check added
  3. EPSS band changecritical → high
  4. Nuclei check added
  5. Patch availablerecord updated
  6. Publishedweakness classified, att&ck mapped

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability NoneNo availability impact

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 46 more references. See all after sign-in

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