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TI-2021-13697 Aliases CVE-2021-34697GHSA-7jmp-v8mh-4f8r

Cisco IOS XE Software Protection Against Distributed Denial of Service Attacks Feature Vulnerability

Priority MEDIUM 46CWE-665Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

A vulnerability in the Protection Against Distributed Denial of Service Attacks feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct denial of service (DoS) attacks to or through the affected device. This vulnerability is due to incorrect programming of the half-opened connections limit, TCP SYN flood limit, or TCP SYN cookie features when the features are configured in vulnerable releases of Cisco IOS XE Software. An attacker could exploit this vulnerability by attempting to flood traffic to or through the affected device. A successful exploit could allow the attacker to initiate a DoS attack to or through an affected device.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01328 71st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco IOS XE Softwareall versions—No fix listedCNA
  • Cisco IOS XE Software VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*17.3.1 to before 17.3.3VulnerableCisco
  • cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:* Versions 17.3.1 to before 17.3.3 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-34697
  2. 2026-10-03 Alias added: GHSA-7jmp-v8mh-4f8r

References

Advisory 1

  • TI-2023-06904 Cisco is providing an update for the ongoing investigation into observed exploitation of… KEVCVSS 3.1CRITICAL 10.0
  • TI-2018-00122 Memory corruption in Cisco IOS and IOS XE KEVCVSS 3.1CRITICAL 9.8
  • TI-2017-02977 Improper input validation in Cisco IOS and IOS XE Software KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-00135 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.8
  • TI-2017-04498 Memory corruption in Cisco IOS KEVCVSS 3.1HIGH 8.8
  • TI-2017-04497 Memory corruption in Cisco IOS XE Software KEVCVSS 3.1HIGH 8.8
See all 561 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences