CVE-2020-17518
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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 49.1%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 49.10% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-23, CWE-22
- Affected
- apache/flink
- Source
- security@apache.org
EPSS moved from 51.4% on 27 September 2026 to 49.1% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- http://www.openwall.com/lists/oss-security/2021/01/05/1Mailing List, Third Party Advisory
- https://lists.apache.org/thread.html/r0b000dc028616d33cb9aa388eb45d516b789cab0024dad94bc06588a%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r1125f3044a0946d1e7e6f125a6170b58d413ebd4a95157e4608041c7%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/r229167538863518738e02f4c1c5a8bb34c1d45dadcc97adf6676b0c1%40%3Cdev.flink.apache.org%3E
- https://lists.apache.org/thread.html/r26fcdd4fe288323006253437ebc4dd6fdfadfb5e93465a0e4f68420d%40%3Cuser-zh.flink.apache.org%3E
- https://lists.apache.org/thread.html/r28f17e564950d663e68cc6fe75756012dda62ac623766bb9bc5e7034%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r4a87837518804b31eb9db3048347ed2bb7b46fbaad5844f22a9fd4dc%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r5444acac3407ef6397d6aef1b5aec2db53b4b88ef221e63084c1e5f2%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r705fb2211b82c9f1f8d2b1d4c823bcbca50402ba09b96608ec657efe%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r710693b0d3b229c81f485804ea1145b4edda79c9e77d66c39a0a2ff1%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r7b2ee88c66fc1d0823e66475631f5c3e7f0365204ff0cb094d9f2433%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r8167f30c4c60a11b8d5be3f55537beeda629be61196e693bde403b36%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r88200d2f0b620c6b4b1585a7171355005c89e678b01d0e71a16c57e7%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r90890afea72a9571d666820b2fe5942a0a5f86be406fa31da3dd0922%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/ra8c96bf3ccb4e491f9ce87ba35f134b4449beb2a38d1ce28fd89001f%40%3Cdev.flink.apache.org%3E
- https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3EMailing List, Vendor Advisory
- https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3EMailing List, Vendor Advisory
- https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3EMailing List, Vendor Advisory
- https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3EMailing List, Vendor Advisory
- https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cuser.flink.apache.org%3E
- https://lists.apache.org/thread.html/rcb9e8af775f2a3706b69153aefde78f208871649df057c70ce2e24f9%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/rd2467344f88bcaf108b8209ca92da8ec393c68174bfb8c27d1e20faa%40%3Cdev.flink.apache.org%3E
- https://lists.apache.org/thread.html/rd6a1a0e2d73220a65a8f6535bbcd24bb66adb0d046c4a1aa18777cf3%40%3Cdev.flink.apache.org%3E
- https://lists.apache.org/thread.html/rec0d650fbd4ea1a5e1224a347d83a63cb44291c334ad58b8809bc23b%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/rf8812a5703f4a5f1341138baf239258b250875699732cfdf9d55b21d%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/rfe159ccf496d75813f24c6079c5d33872d83f5a2e39cb32c3aef5a73%40%3Cissues.flink.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/01/05/1Mailing List, Third Party Advisory
- https://lists.apache.org/thread.html/r0b000dc028616d33cb9aa388eb45d516b789cab0024dad94bc06588a%40%3Cissues.flink.apache.org%3E
- https://lists.apache.org/thread.html/r1125f3044a0946d1e7e6f125a6170b58d413ebd4a95157e4608041c7%40%3Cannounce.apache.org%3E
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.