Security readout for executives and security teams
Plain-English summary
Certain Juniper routers running affected Junos software can be induced, through BGP routing updates, to send a bad update to another peer. That can drop an established BGP session and interrupt routing availability. The issue is high severity because it is network-reachable, requires no authentication, and repeated updates can extend the outage.
Executive priority
Treat this as a high-priority routing availability issue for Juniper BGP infrastructure. It does not imply data theft, but it can disrupt network reachability. Prioritize upgrade planning for edge, transit, and service-provider routers where BGP session loss would affect customers or critical connectivity.
Technical view
CVE-2020-1632 is a Junos OS and Junos OS Evolved BGP handling flaw. When at least one established BGP session lacks 4-byte AS extension support, receipt of a specific BGP UPDATE can cause the device to advertise an invalid update to other peers, terminating those sessions. CVSS 3.1 is 8.6 with high availability impact.
Likely exposure
Exposure is limited to Juniper Networks Junos OS 16.1 through 19.2 fixed-release gaps and Junos OS Evolved before 19.2R2-EVO. Risk is most relevant on devices with established BGP peering, especially where any peer lacks RFC 4893 4-byte AS support.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. The vulnerability is remotely triggerable through BGP update processing and can create extended denial of service if the triggering update is received repeatedly. No exploit details are provided here.
Researcher notes
The notable condition is the presence of at least one established BGP session without 4-byte AS extension support. The described failure propagates indirectly: one peer sends a specific update, the affected router emits an invalid update, and another peer terminates the session. Evidence does not establish active exploitation.
Mitigation direction
- Upgrade Junos OS or Junos OS Evolved to Juniper fixed releases listed for the affected branch.
- Prioritize internet-edge and transit BGP routers before lower-impact routing environments.
- Review Juniper advisory JSA11013 for branch-specific fixed versions and operational guidance.
- Identify BGP peers or sessions lacking RFC 4893 4-byte AS extension support.
- Monitor BGP session stability until upgrades or vendor guidance are fully applied.
Validation and detection
- Inventory Juniper devices running Junos OS 16.1 through 19.2 or Junos OS Evolved before 19.2R2-EVO.
- Map affected software branches to Juniper's fixed-release thresholds in JSA11013.
- Confirm whether affected devices maintain BGP sessions with peers lacking 4-byte AS support.
- Review BGP logs for unexpected session terminations around UPDATE handling events.
- Confirm upgraded devices are on or beyond the fixed versions for their release branch.
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-755: 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-2020-1632 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
- https://kb.juniper.net/JSA11013CVE reference · x_refsource_CONFIRM
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 Handling of Exceptional Conditions
Improper Handling of Exceptional Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.