CVE-2021-1224

5.3 mediumEPSS 2.0%

Medium (5.3). EPSS 2.0% chance of exploitation in the next 30 days.

Multiple Cisco products are affected by a vulnerability with TCP Fast Open (TFO) when used in conjunction with the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect detection of the HTTP payload if it is contained at least partially within the TFO connection handshake. An attacker could exploit this vulnerability by sending crafted TFO packets with an HTTP payload through an affected device. A successful exploit could allow the attacker to bypass configured file policy for HTTP packets and deliver a malicious payload.

Severity

CVSS 3.1

5.3 medium

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

EPSS: 2.0% chance of exploitation in the next 30 days; higher than 81% of CVEs (scores of 2026-10-31)
CWE: CWE-693
Published: 2021-01-13
Modified: 2026-08-11
Record from: the NVD, synced 2026-10-19

Affected

cisco:ios_xe
cisco:meraki_mx100_firmware
cisco:meraki_mx250_firmware
cisco:meraki_mx450_firmware
cisco:meraki_mx64_firmware
cisco:meraki_mx64w_firmware
cisco:meraki_mx67_firmware
cisco:meraki_mx67c_firmware
cisco:meraki_mx67w_firmware
cisco:meraki_mx68_firmware
cisco:meraki_mx68cw_firmware
cisco:meraki_mx68w_firmware
cisco:meraki_mx84_firmware
cisco:secure_firewall_management_center
cisco:secure_firewall_threat_defense
snort:snort

References

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