CVE-2021-1220

lowpriority · track · 17EPSS 0.010 · 62 %ileEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.98% (62nd) EPSS
CVSS 3.5 · low
Is it mine?
85 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · cisa_csaf_ot

EPSS · scored 2026-10-27

Multiple vulnerabilities in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to cause the web UI software to become unresponsive and consume vty line instances, resulting in a denial of service (DoS) condition. These vulnerabilities are due to insufficient error handling in the web UI. An attacker could exploit these vulnerabilities by sending crafted HTTP packets to an affected device. A successful exploit could allow the attacker to cause the web UI software to become unresponsive and consume all available vty lines, preventing new session establishment and resulting in a DoS condition. Manual intervention would be required to regain web UI and vty session functionality. Note: These vulnerabilities do not affect the console connection.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

5.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.5–5.5

v2.03.5lowAV:N/AC:M/Au:S/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 6.8 · impact 2.9
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lprimary · NVD / NIST USexploitability 2.8 · impact 1.4
v3.05.5mediumCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:Nsecondary · CISA US
v3.14.3mediumAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · FSTEC (BDU) RU
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · ENISA EU
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · psirt@cisco.com USexploitability 2.8 · impact 1.4
v3.14mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:Usecondary · CVSS-BT (t0sche)
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · Cisco PSIRT US
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USCWE-20USCWE-20US
04

affected products (85)

Products and version ranges known to be affected.

showing 20 of 85
05

advisories (2)

Vendor and ecosystem advisories describing this.

  • cisco-sa-xe-webui-dos-z9yqYQAnCisco IOS XE Software Web UI Denial of Service Vulnerabilities2021-03-24csaf · cisco_csafUS

    Multiple vulnerabilities in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to cause the web UI software to become unresponsive and consume vty line instances, resulting in a denial of service (DoS) condition. These vulnerabilities are due to insufficient error handling in the web UI. An attacker could exploit these vulnerabilities by sending crafted HTTP packets to an affected device. A successful exploit could allow the attacker to cause the web UI software to become unresponsive and consume all available vty lines, preventing new session establishment and resulting in a DoS condition. Manual intervention would be required to regain web UI and vty session functionality. Note: These vulnerabilities do not affect the console connection. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

  • ICSA-21-110-02ICSA-21-110-02_Rockwell Automation Stratix Switches2021-04-20icsa · cisa_csaf_otUS

    Cisco reported these vulnerabilities to Rockwell Automation.

06

also known as (4)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisa_csaf_otcisco_csafNVDCVE.orgMITRE
published 2021-03-24modified 2026-06-17
08

references (6)

External citations — patches, advisories, analysis.

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