{"id":"CVE-2021-33541","aliases":["EUVD-2021-20233","GHSA-jwj9-vx74-vv26"],"status":"published","title":"Phoenix Contact: ILC1x Industrial controllers affected by Denial-of-Service vulnerability","description":"Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected by a Denial-of-Service vulnerability. The communication protocols and device access do not feature authentication measures. Remote attackers can use specially crafted IP packets to cause a denial of service on the PLC's network communication module. A successful attack stops all network communication. To restore the network connectivity the device needs to be restarted. The automation task is not affected.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01493,"percentile":0.74365,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-770"],"published":"2021-06-25T18:26:05Z","modified":"2026-06-17T03:54:45Z","products":[{"vendor":"phoenix contact","product":"ilc1x"},{"vendor":"phoenixcontact","product":"ilc1x0_firmware"},{"vendor":"phoenixcontact","product":"ilc1x1_firmware"}],"references":[{"url":"https://cert.vde.com/en-us/advisories/vde-2021-019","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-33541"},{"url":"https://github.com/advisories/GHSA-jwj9-vx74-vv26"}],"sources":{"cve":[{"id":"CVE-2021-33541","title":"Phoenix Contact: ILC1x Industrial controllers affected by Denial-of-Service vulnerability","description":"Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected by a Denial-of-Service vulnerability. The communication protocols and device access do not feature authentication measures. Remote attackers can use specially crafted IP packets to cause a denial of service on the PLC's network communication module. A successful attack stops all network communication. To restore the network connectivity the device needs to be restarted. The automation task is not affected.","status":"published","published":"2021-06-25T18:26:05.564Z","modified":"2024-09-16T23:21:50.885Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:33:10.555814Z"}],"euvd":[{"id":"EUVD-2021-20233","description":"Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected by a Denial-of-Service vulnerability. The communication protocols and device access do not feature authentication measures. Remote attackers can use specially crafted IP packets to cause a denial of service on the PLC's network communication module. A successful attack stops all network communication. To restore the network connectivity the device needs to be restarted. The automation task is not affected.","status":"published","published":"2021-06-25T18:26:05Z","modified":"2024-09-16T23:21:50Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-03T00:54:54.099071Z"}],"ghsa":[{"id":"GHSA-jwj9-vx74-vv26","title":"Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected...","description":"Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected by a Denial-of-Service vulnerability. The communication protocols and device access do not feature authentication measures. Remote attackers can use specially crafted IP packets to cause a denial of service on the PLC's network communication module. A successful attack stops all network communication. To restore the network connectivity the device needs to be restarted. The automation task is not affected.","status":"published","published":"2022-05-24T19:06:16Z","modified":"2023-01-30T05:00:31Z","cwes":["CWE-770"],"updated_at":"2026-11-02T14:46:13.539888Z"}],"nvd":[{"id":"CVE-2021-33541","description":"Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected by a Denial-of-Service vulnerability. The communication protocols and device access do not feature authentication measures. Remote attackers can use specially crafted IP packets to cause a denial of service on the PLC's network communication module. A successful attack stops all network communication. To restore the network connectivity the device needs to be restarted. The automation task is not affected.","status":"published","published":"2021-06-25T19:15:09.757Z","modified":"2026-06-17T03:54:45.35Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":7.8,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:06:55.259633Z"}]}}