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NVD / CVE Program· CNA juniper

CVE-2024-39559: Junos OS Evolved: Receipt of a specific TCP packet may result in a system crash (vmcore) on dual RE systems with NSR enabled

Noroxi assessment

Priority: Monitor (action score 32/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.39% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Juniper Networks Junos OS Evolved 21.2R3-S8-EVO, 21.4R3-S6-EVO, 22.1R3-S4-EVO.
  • Severity is disputed: the assigning authority (CNA) scores it 5.9, NVD 8.2.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Juniper Networks Junos OS Evolved 21.2R3-S8-EVO, 21.4R3-S6-EVO, 22.1R3-S4-EVO or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

An Improper Check for Unusual or Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS Evolved may allow a network-based unauthenticated attacker to crash the device (vmcore) by sending a specific TCP packet over an established TCP session with MD5 authentication enabled, destined to an accessible port on the device, resulting in a Denial of Service (DoS).  The receipt of this packet must occur within a specific timing window outside the attacker's control (i.e., race condition). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects dual RE systems with Nonstop Active Routing (NSR) enabled. Exploitation can only occur over TCP sessions with MD5 authentication enabled (e.g., BGP with MD5 authentication). This issue affects Junos OS Evolved:  * All versions before 21.2R3-S8-EVO, * from 21.4-EVO before 21.4R3-S6-EVO, * from 22.1-EVO before 22.1R3-S4-EVO, * from 22.2-EVO before 22.2R3-S4-EVO, * from 22.3-EVO before 22.3R3-S3-EVO, * from 22.4-EVO before 22.4R2-S2-EVO, 22.4R3-EVO.

HighCVSS 8.2 · v4.0—No exploit Fix available
Published
Jul 10, 2024
Updated
Jun 17, 2026
EPSS
0.3% · 34th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · juniper
5.9
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2024-39559

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
juniperjunos os evolved

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • juniper junos os evolvedbefore 21.2
  • juniper junos os evolved21.2
  • juniper junos os evolved21.4
  • juniper junos os evolved22.1
  • juniper junos os evolved22.2
  • juniper junos os evolved22.3
  • juniper junos os evolved22.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (juniper). Independent of NVD's CPE analysis and usually ahead of it.

  • Juniper Networks Junos OS Evolved

    • before 21.2R3-S8-EVOaffected · semver
    • 21.4-EVO and later · before 21.4R3-S6-EVOaffected · semver
    • 22.1-EVO and later · before 22.1R3-S4-EVOaffected · semver
    • 22.2-EVO and later · before 22.2R3-S4-EVOaffected · semver
    • 22.3-EVO and later · before 22.3R3-S3-EVOaffected · semver
    • 22.4-EVO and later · before 22.4R2-S2-EVO, 22.4R3-EVOaffected · semver

Same product

juniper: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-21902Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root
    43Plan
  • CVE-2026-101990Junos OS and Junos OS Evolved: A BGP peer causes an rpd crash when flow-spec routes are re-advertised
    37Monitor
  • CVE-2026-101986Junos OS and Junos OS Evolved: J-Web permits pre-authentication CGI execution
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2024-39513Jul 10, 2024 · Junos OS Evolved: Execution of a specific CLI command will cause a crash in the AFT manager
    27Monitor
  • ← EarlierCVE-2024-39557Jul 10, 2024 · Junos OS Evolved: MAC table changes cause a memory leak
    28Monitor
  • Later →CVE-2024-39562Jul 10, 2024 · Junos OS Evolved: A high rate of SSH connections causes a Denial of Service
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Juniper Networks Junos OS Evolved21.2R3-S8-EVOVendor (CNA)
Juniper Networks Junos OS Evolved21.4R3-S6-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.1R3-S4-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.2R3-S4-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.3R3-S3-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.4R2-S2-EVO, 22.4R3-EVOVendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2024-395191 days apartJunos OS Evolved: ACX 7000 Series: Multicast traffic is looped in a multihoming EVPN MPLS scenario
    28Monitor
  • CVE-2024-395351 days apartJunos OS Evolved: ACX 7000 Series: When specific traffic is received in a VPLS scenario evo-pfemand crashes
    28Monitor
  • CVE-2025-59958456 days apartJunos OS Evolved: PTX Series: When a firewall filter rejects traffic these packets are erroneously sent to the RE
    27Monitor
  • CVE-2023-44196272 days apartJunos OS Evolved: PTX10003 Series: Packets which are not destined to the router can reach the RE
    26Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-754 · Improper Check for Unusual or Exceptional Conditions

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:A/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records