CVE & CISA-KEV Catalog

CVE-2021-34739

HIGHEPSS 74th pctl
8.1
CVSS v3
NVD

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.

How to fix

Remediation Available
sf500-24 firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sf500-24mp firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sf500-24p firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sf500-48 firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sf500-48mp firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sf500-48p firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500-28 firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500-28mpp firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500-28p firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500-52 firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500-52mp firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500-52p firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500x-24 firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500x-24mpp firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500x-24p firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500x-48 firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500x-48mp firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500x-48p firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD
sg500xg-8f8t firmwareNVD
Affected:>= 2.5.5.0, < 2.5.8.12Fixed in:2.5.8.12CVE-2021-34739derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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

Exploit Intelligence

1.62%probability of exploitation in 30 days
74thpercentile

Elevated risk: more likely to be exploited than 74% of all known CVEs.

References

Vendor Advisory1

Related Vulnerabilities

Other CWE-613 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2014-2595Critical9.817%--
CVE-2023-30403High7.514%--
CVE-2020-27422Critical9.87.8%--
CVE-2014-3616Medium4.35.7%-Fix
CVE-2021-3144Critical9.15.2%-Fix
CVE-2021-24019High8.13.9%-Fix

Common questions

How do I fix CVE-2021-34739?

Published advisories record a fix for 19 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2021-34739 being actively exploited?

Not that we know of. CVE-2021-34739 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.6% is the estimated probability that it will be exploited in the next 30 days. That is higher than 74% of all scored CVEs.

How severe is CVE-2021-34739?

CVE-2021-34739 has a CVSS v3 base score of 8.1, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-34739 affect?

Published advisories record a fix for sf500-24 firmware (NVD), sf500-24mp firmware (NVD), sf500-24p firmware (NVD), sf500-48 firmware (NVD), and 15 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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CVE-2021-34739 severity badge

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.