{"id":"CVE-2020-1999","aliases":["EUVD-2020-12789","GHSA-6p97-xh7r-7cmv"],"status":"published","title":"PAN-OS: Threat signatures are evaded by specifically crafted packets","description":"A vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine that allows an attacker to communicate with devices in the network in a way that is not analyzed for threats by sending data through specifically crafted TCP packets. This technique evades signature-based threat detection. This issue impacts: PAN-OS 8.1 versions earlier than 8.1.17; PAN-OS 9.0 versions earlier than 9.0.11; PAN-OS 9.1 versions earlier than 9.1.5; All versions of PAN-OS 7.1 and PAN-OS 8.0.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.01337,"percentile":0.71607,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-754"],"published":"2020-11-12T00:05:19Z","modified":"2026-06-17T03:02:48Z","products":[{"vendor":"palo alto networks","product":"pan-os"},{"vendor":"paloaltonetworks","product":"pan-os"}],"references":[{"url":"https://security.paloaltonetworks.com/CVE-2020-1999","tags":["x_refsource_MISC","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-1999"},{"url":"https://github.com/advisories/GHSA-6p97-xh7r-7cmv"}],"sources":{"cve":[{"id":"CVE-2020-1999","title":"PAN-OS: Threat signatures are evaded by specifically crafted packets","description":"A vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine that allows an attacker to communicate with devices in the network in a way that is not analyzed for threats by sending data through specifically crafted TCP packets. This technique evades signature-based threat detection. This issue impacts: PAN-OS 8.1 versions earlier than 8.1.17; PAN-OS 9.0 versions earlier than 9.0.11; PAN-OS 9.1 versions earlier than 9.1.5; All versions of PAN-OS 7.1 and PAN-OS 8.0.","status":"published","published":"2020-11-12T00:05:19.633Z","modified":"2024-09-17T01:15:53.377Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-754"],"updated_at":"2026-11-02T14:35:56.638833Z"}],"euvd":[{"id":"EUVD-2020-12789","description":"A vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine that allows an attacker to communicate with devices in the network in a way that is not analyzed for threats by sending data through specifically crafted TCP packets. This technique evades signature-based threat detection. This issue impacts: PAN-OS 8.1 versions earlier than 8.1.17; PAN-OS 9.0 versions earlier than 9.0.11; PAN-OS 9.1 versions earlier than 9.1.5; All versions of PAN-OS 7.1 and PAN-OS 8.0.","status":"published","published":"2020-11-12T00:05:19Z","modified":"2024-09-17T01:15:53Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-03T00:28:51.722495Z"}],"ghsa":[{"id":"GHSA-6p97-xh7r-7cmv","title":"A vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine...","description":"A vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine that allows an attacker to communicate with devices in the network in a way that is not analyzed for threats by sending data through specifically crafted TCP packets. This technique evades signature-based threat detection. This issue impacts: PAN-OS 8.1 versions earlier than 8.1.17; PAN-OS 9.0 versions earlier than 9.0.11; PAN-OS 9.1 versions earlier than 9.1.5; All versions of PAN-OS 7.1 and PAN-OS 8.0.","status":"published","published":"2022-05-24T17:33:54Z","modified":"2023-01-29T05:04:41Z","cwes":["CWE-754"],"updated_at":"2026-11-02T14:45:36.996717Z"}],"nvd":[{"id":"CVE-2020-1999","description":"A vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine that allows an attacker to communicate with devices in the network in a way that is not analyzed for threats by sending data through specifically crafted TCP packets. This technique evades signature-based threat detection. This issue impacts: PAN-OS 8.1 versions earlier than 8.1.17; PAN-OS 9.0 versions earlier than 9.0.11; PAN-OS 9.1 versions earlier than 9.1.5; All versions of PAN-OS 7.1 and PAN-OS 8.0.","status":"published","published":"2020-11-12T00:15:10.253Z","modified":"2026-06-17T03:02:48.18Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-754"],"updated_at":"2026-11-02T14:06:24.137599Z"}]}}