{"cve":"CVE-2021-34739","nvd":{"published":"2021-11-04T16:15:08.577","modified":"2026-06-17T03:56:27.877","status":"Modified","description":"A vulnerability in the web-based management interface of multiple Cisco Small Business Series Switches could allow an unauthenticated, remote attacker to replay valid user session credentials and gain unauthorized access to the web-based management interface of an affected device. This vulnerability is due to insufficient expiration of session credentials. An attacker could exploit this vulnerability by conducting a man-in-the-middle attack against an affected device to intercept valid session credentials and then replaying the intercepted credentials toward the same device at a later time. A successful exploit could allow the attacker to access the web-based management interface with administrator privileges.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-613"],"references":["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-switches-tokens-UzwpR4e5","https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-switches-tokens-UzwpR4e5"],"products":["cisco:cbs250-16p-2g_firmware","cisco:cbs250-16t-2g_firmware","cisco:cbs250-24fp-4g_firmware","cisco:cbs250-24fp-4x_firmware","cisco:cbs250-24p-4g_firmware","cisco:cbs250-24p-4x_firmware","cisco:cbs250-24pp-4g_firmware","cisco:cbs250-24t-4g_firmware","cisco:cbs250-24t-4x_firmware","cisco:cbs250-48p-4g_firmware","cisco:cbs250-48p-4x_firmware","cisco:cbs250-48pp-4g_firmware","cisco:cbs250-48t-4g_firmware","cisco:cbs250-48t-4x_firmware","cisco:cbs250-8fp-e-2g_firmware","cisco:cbs250-8p-e-2g_firmware","cisco:cbs250-8pp-d_firmware","cisco:cbs250-8pp-e-2g_firmware","cisco:cbs250-8t-d_firmware","cisco:cbs250-8t-e-2g_firmware","cisco:cbs350-12np-4x_firmware","cisco:cbs350-12xs_firmware","cisco:cbs350-12xt_firmware","cisco:cbs350-16fp-2g_firmware","cisco:cbs350-16p-2g_firmware","cisco:cbs350-16p-e-2g_firmware","cisco:cbs350-16t-2g_firmware","cisco:cbs350-16t-e-2g_firmware","cisco:cbs350-16xts_firmware","cisco:cbs350-24fp-4g_firmware","cisco:cbs350-24fp-4x_firmware","cisco:cbs350-24mgp-4x_firmware","cisco:cbs350-24ngp-4x_firmware","cisco:cbs350-24p-4g_firmware","cisco:cbs350-24p-4x_firmware","cisco:cbs350-24s-4g_firmware","cisco:cbs350-24t-4g_firmware","cisco:cbs350-24t-4x_firmware","cisco:cbs350-24xs_firmware","cisco:cbs350-24xt_firmware","cisco:cbs350-24xts_firmware","cisco:cbs350-48fp-4g_firmware","cisco:cbs350-48fp-4x_firmware","cisco:cbs350-48ngp-4x_firmware","cisco:cbs350-48p-4g_firmware","cisco:cbs350-48p-4x_firmware","cisco:cbs350-48t-4g_firmware","cisco:cbs350-48t-4x_firmware","cisco:cbs350-48xt-4x_firmware","cisco:cbs350-8fp-2g_firmware"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-34739","score":0.0167,"percentile":0.76801,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}