Security readout for executives and security teams
Plain-English summary
This is a service disruption risk in Cisco ASR 5000 Series Software (StarOS). A remote unauthenticated attacker could send malformed IKEv2 traffic that makes the ipsecmgr process restart, temporarily interrupting ongoing IKE negotiations. The provided sources do not indicate data theft or system takeover.
Executive priority
Schedule remediation in the normal vulnerability cycle, with faster handling for carrier, VPN, or mobile-core services where IKE negotiation disruption affects customers. This is not a critical compromise scenario in the provided sources, but it can affect service availability.
Technical view
The flaw is insufficient validation of incoming IKEv2 packets in the StarOS ipsecmgr process, mapped to CWE-119. CVSS 3.1 is 5.3 with network attack vector, low complexity, no privileges, no user interaction, and low availability impact. Cisco says software updates are available and no workaround addresses it.
Likely exposure
Organizations are exposed if they operate Cisco ASR 5000 Series Software versions listed as affected and receive IKEv2/IPsec traffic on those systems. Internet or untrusted-network reachability increases operational risk. The source bundle does not identify other affected Cisco products.
Exploitation context
The source bundle supports remote unauthenticated denial of service through malformed IKEv2 packets. It does not state active exploitation, public exploit availability, or CISA KEV listing. Treat exploitation as plausible but not confirmed in the provided evidence.
Researcher notes
Focus validation on StarOS version, ipsecmgr exposure, and observed availability impact. Do not assume confidentiality or integrity impact beyond the CVSS vector. Cisco’s no-workaround statement makes patch verification the central remediation evidence.
Mitigation direction
- Upgrade affected Cisco ASR 5000 Series Software using Cisco’s advisory guidance.
- Prioritize systems that process IKEv2/IPsec traffic from untrusted networks.
- Apply exposure reduction controls where operationally feasible until patched.
- Monitor Cisco guidance because the advisory states there are no workarounds.
Validation and detection
- Inventory Cisco ASR 5000 Series Software versions against Cisco’s affected version list.
- Confirm whether ASR 5000 devices accept IKEv2 traffic from untrusted networks.
- Review logs for unexpected ipsecmgr restarts or IKE negotiation interruptions.
- Verify upgraded versions are listed by Cisco as fixed or not affected.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-119: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-1424 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/RL:X/RC:X/E:X
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/RL:X/RC:X/E:X3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/RL:X/RC:X/E:X
Source materials
- CVE List V5 sourceCVE List V5
- cisco-sa-staros-ipsecmgr-dos-3gkHXwvSCVE reference
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-xss-webui-gQLSFyPM</a></p><p>This advisory is part of the October 2021 release of the Cisco ASA, FTD, and FMC Security Advisory Bundled publication. For a complete list of the advisories and links to them, see <a href="https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74773">Cisco Event Response: October 2021 Cisco ASA, FMC, and FTD Software Security Advisory Bundled PublicationCVE reference
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-sigverbypass-gPYXd6MkCVE reference
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-sma-info-disclo-VOu2GHbZCVE reference
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xrbgp-rpki-dos-gvmjqxbk</a></p><p>This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see <a href="https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74637">Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled PublicationCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Restriction of Operations within the Bounds of a Memory Buffer
Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.