JunosOperating system · Juniper

CVE-2024-21598

HIGH · 7.5 CVSS v3.1 Published 2024-04-12

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

84/100

Remediation priority · High

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

An Improper Validation of Syntactic Correctness of Input vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). If a BGP update is received over an established BGP session which contains a tunnel encapsulation attribute with a specifically malformed TLV, rpd will crash and restart. This issue affects Juniper Networks Junos OS: * 20.4 versions 20.4R1 and later versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S7; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S4; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R3; * 23.2 versions earlier than 23.2R1-S2, 23.2R2; Junos OS Evolved: * 20.4-EVO versions 20.4R1-EVO and later versions earlier than 20.4R3-S9-EVO; * 21.2-EVO versions earlier than 21.2R3-S7-EVO; * 21.3-EVO versions earlier than 21.3R3-S5-EVO; * 21.4-EVO versions earlier than 21.4R3-S5-EVO; * 22.1-EVO versions earlier than 22.1R3-S4-EVO; * 22.2-EVO versions earlier than 22.2R3-S3-EVO; * 22.3-EVO versions earlier than 22.3R3-S1-EVO; * 22.4-EVO versions earlier than 22.4R3-EVO; * 23.2-EVO versions earlier than 23.2R1-S2-EVO, 23.2R2-EVO; This issue does not affect Juniper Networks * Junos OS versions earlier than 20.4R1; * Junos OS Evolved versions earlier than 20.4R1-EVO. This is a related but separate issue than the one described in JSA79095.

Technical summary

dbcve analysis · high confidence

A parsing vulnerability in Juniper's Routing Protocol Daemon (rpd) allows an unauthenticated network attacker to send a malformed BGP tunnel encapsulation attribute TLV, causing rpd to crash and restart, resulting in Denial of Service.

MitigationUpgrade Junos OS or Junos OS Evolved to the fixed versions (20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1, 22.4R3, 23.2R1-S2, 23.2R2 or later) as specified in the advisory.

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

Affected products & versions

NVD · CPE data

JunosOperating system

Affected:= 20.4= 21.2= 21.3= 21.4= 22.1= 22.2= 22.3= 22.4= 23.2

Junos Os EvolvedOperating system

Affected:= 20.4= 21.2= 21.3= 21.4= 22.1= 22.2= 22.3= 22.4= 23.2

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Am I affected?

dbcve checks

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

Check Junos OS version

Run 'show version' command on the Juniper device to obtain the installed Junos version.

Affected if The version matches any of these affected releases: 20.4, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, 22.4, or 23.2 (without the vendor-supplied fixes)
Verify BGP is enabled

Run 'show bgp summary' or 'show protocols bgp' to confirm BGP is configured and active.

Affected if BGP protocol is enabled and the device is acting as a BGP peer
Confirm BGP neighbor exposure

Run 'show bgp neighbor' to list configured BGP peers and their connection status.

Affected if There are active BGP neighbors, particularly untrusted or external peers (e.g., eBGP)
Check for rpd crash logs

Run 'show log messages' or 'show system core-dumps' to look for recent rpd crash events, especially related to BGP attribute parsing.

Affected if Recent rpd crashes or restarts are logged with BGP-related error messages

The device is affected if it runs a vulnerable Junos version (20.4, 21.2-21.4, 22.1-22.4, or 23.2) and has BGP enabled with external network exposure.

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

Remediation

dbcve · scoped

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Upgrade Junos OS or Junos OS Evolved to the fixed versions (20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1, 22.4R3, 23.2R1-S2, 23.2R2 or later) as specified in the advisory.

Recommended fix High confidence

Upgrade to 22.4R3 or later (or 23.2R1-S2/23.2R2 for 23.2 branch) to obtain the fix. Earlier branch users should upgrade to 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, or 21.4R3-S5 respectively.

1. Identify the current Junos OS or Junos OS Evolved version running on the device using 'show version'
2. Based on the current version branch, upgrade to the first fixed release: 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1, 22.4R3, or 23.2R1-S2/23.2R2
3. For Junos OS Evolved, upgrade to the corresponding -EVO fixed releases: 20.4R3-S9-EVO, 21.2R3-S7-EVO, 21.3R3-S5-EVO, 21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S3-EVO, 22.3R3-S1-EVO, 22.4R3-EVO, or 23.2R1-S2-EVO/23.2R2-EVO
4. Download the upgrade package from the Juniper Networks support portal
5. Upload the package to the device and initiate the upgrade using 'request system software add <package>'
6. After upgrade completes, verify the new version with 'show version'
7. Confirm rpd is running stable and BGP sessions are established using 'show bgp summary'

Caveat Review Juniper release notes for any potential compatibility issues or configuration changes between your current version and the target fixed release before upgrading.

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

Fix this in Junos Scoped from the published advisory

Consultation3.0 h
Implementation4.0 h
Testing2.0 h
Review / QA1.0 h

10.0 hours of engineering $1,800

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Scan for this in your stack

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References

Primary sources

supportportal.juniper.netVendor Advisory
www.first.orgNot Applicable
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-21598 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2024-21598?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsA vendor remedy is published

Severity 7.5 High

Exploit likelihood EPSS, next 30 days 0.6%

Affects: Junos

Remediation

A high-priority fix

Fix this in Junos 10 hrs · Moderate

Typical engagement from $1,800

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2024-21598 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References