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JunosOperating system · Juniper

CVE-2022-22220

MEDIUM · 5.9 CVSS v3.1 Published 2022-10-18
Fix available
A fix is available. Upgrade to 18.4 / 20.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in Routing Protocol Daemon (rpd) of Juniper Networks Junos OS, Junos OS Evolved allows a network-based unauthenticated attacker to cause a Denial of Service (DoS). When a BGP flow route with redirect IP extended community is received, and the reachability to the next-hop of the corresponding redirect IP is flapping, the rpd process might crash. Whether the crash occurs depends on the timing of the internally processing of these two events and is outside the attackers control. Please note that this issue also affects Route-Reflectors unless 'routing-options flow firewall-install-disable' is configured. This issue affects: Juniper Networks Junos OS: 18.4 versions prior to 18.4R2-S10, 18.4R3-S10; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R1-S8, 19.2R3-S4; 19.4 versions prior to 19.4R3-S8; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S2; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-EVO; 21.1-EVO versions prior to 21.1R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 18.4R1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A Time-of-check Time-of-use (TOCTOU) race condition in Juniper's Routing Protocol Daemon (rpd) allows an unauthenticated network attacker to cause denial of service. When a BGP flow route with redirect IP extended community is received while the next-hop reachability is flapping, the rpd process can crash depending on the timing of internal event processing.

MitigationApply vendor-supplied patches for affected Junos OS/Evolved versions. For Route-Reflectors, consider configuring 'routing-options flow firewall-install-disable' as a workaround if flow route processing is not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:< 18.4= 18.4= 19.1= 19.4= 20.2= 20.3= 20.4= 21.1
Junos Os EvolvedOperating system
Affected:< 20.4= 20.4= 21.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check the Junos version
    Run 'show version' or 'show version detail' to identify the installed Junos OS or Junos OS Evolved version
    Affected if The installed version matches one of the affected ranges: Junos < 18.4, = 18.4, = 19.1, = 19.4, = 20.2, = 20.3, = 20.4, = 21.1 (for Junos) or < 20.4, = 20.4, = 21.1 (for Junos Evolved)
  2. Verify BGP is configured
    Run 'show bgp summary' or 'show configuration protocols bgp' to determine if BGP is actively configured
    Affected if BGP is configured and operational, as the flaw is triggered by BGP flow route processing in rpd
  3. Check for flow route configuration
    Run 'show configuration firewall' or 'show firewall' to identify if flow-based filtering (firewall filters with 'then accept' or 'then discard' combined with flow routes) is configured
    Affected if Flow routes are configured, as the vulnerability specifically triggers when processing BGP flow routes with redirect IP extended community
  4. Identify redirect IP extended community usage
    Review BGP configuration for 'redirect-ip' extended community under the 'protocols bgp' hierarchy, or examine active flow route policies using 'show policy' and 'show route flow'
    Affected if BGP flow routes include redirect IP extended community, which is the specific condition that triggers the race condition during next-hop flapping
  5. Monitor rpd process stability
    Run 'show system processes extensive | match rpd' or check 'show log messages' for rpd crash events, particularly around times of BGP next-hop flapping
    Affected if The rpd process has crashed or exhibits instability when BGP flow routes with redirect IP extended community are processed during next-hop reachability changes

A system is affected if it runs an affected Junos version, has BGP configured with flow routes that use redirect IP extended community, and experiences rpd crashes during BGP next-hop reachability changes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 18.4 / 20.4 or later
Fixed in 18.420.4
Interim mitigation

Apply vendor-supplied patches for affected Junos OS/Evolved versions. For Route-Reflectors, consider configuring 'routing-options flow firewall-install-disable' as a workaround if flow route processing is not required.

Recommended fix High confidence

Upgrade to Junos OS 20.4R3 or later (21.1R2, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, 22.4) / Junos OS Evolved 20.4R2-EVO or later (21.1R2-EVO, 21.2-EVO, 21.3-EVO, 21.4-EVO, 22.1-EVO, 22.2-EVO)

  1. 1. Identify the current Junos OS or Junos OS Evolved version running on the device using 'show version'
  2. 2. Determine if the device is acting as a Route-Reflector; if so, consider applying 'set routing-options flow firewall-install-disable' as a temporary mitigation
  3. 3. For Junos OS: upgrade to one of the fixed versions: 18.4R2-S10 or later, 18.4R3-S10 or later, 19.1R3-S7 or later, 19.2R1-S8 or later, 19.2R3-S4 or later, 19.4R3-S8 or later, 20.2R3-S3 or later, 20.3R3-S2 or later, 20.4R3 or later, or 21.1R2 or later
  4. 4. For Junos OS Evolved: upgrade to 20.4R2-EVO or later, or 21.1R2-EVO or later
  5. 5. After upgrade, verify rpd process stability using 'show system processes extensive | match rpd'
  6. 6. Verify BGP peers are up using 'show bgp summary'
Caveat Standard Junos upgrade considerations apply - review release notes for any changes to features or configuration syntax; ensure compatibility with hardware platform

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2022-22220 in production — separate from our analysis above.

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