Security readout for executives and security teams
Plain-English summary
CVE-2021-1313 is a high-severity denial-of-service issue in Cisco IOS XR Software. A remote attacker without authentication could trigger availability loss on an affected device through ingress packet processing. The business risk is network disruption, not data theft, based on the supplied CVSS vector.
Executive priority
High priority for organizations relying on Cisco IOS XR infrastructure. The issue threatens service availability and could affect routing or network operations. Prioritize validation and vendor-guided remediation, especially on externally reachable or business-critical devices.
Technical view
The CVE describes multiple ingress packet processing vulnerabilities in Cisco IOS XR Software, associated with Enf Broker DoS. CVSS 3.1 is 8.6 with network attack vector, low complexity, no privileges, no user interaction, changed scope, and high availability impact only.
Likely exposure
Organizations using Cisco IOS XR Software on network infrastructure may be exposed. The source bundle does not identify exact affected versions, device models, or vulnerable configurations, so exposure requires comparison against Cisco's advisory and local IOS XR inventory.
Exploitation context
The provided sources do not state active exploitation, and the CVE is not marked KEV. Treat exploitation as plausible because the vector is remote, unauthenticated, and low complexity, but do not claim real-world exploitation from this bundle alone.
Researcher notes
Evidence is sufficient for vulnerability class, severity, and attack vector, but incomplete for affected versions, fixed releases, workarounds, and product-specific validation. Use the Cisco advisory as the controlling source before making remediation claims.
Mitigation direction
- Review Cisco's advisory for affected releases and fixed software guidance.
- Prioritize Cisco IOS XR remediation for internet-facing or critical routing infrastructure.
- Ask Cisco support for validated interim mitigations if upgrades cannot be scheduled promptly.
- Monitor affected network devices for unexplained availability loss until remediation is complete.
Validation and detection
- Inventory all Cisco IOS XR Software deployments and record exact software versions.
- Compare local versions and platforms against Cisco's advisory details.
- Confirm whether exposed devices process untrusted ingress traffic.
- Review monitoring for recent unexplained device resets, packet-processing failures, or availability events.
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-399: 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-2021-1313 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
- High
- CVSS
- 8.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
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:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210203 Cisco IOS XR Software Enf Broker Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
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.
Resource Management Errors
Resource Management Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.