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NVD / CVE Program· CNA juniper

CVE-2024-39555: Junos OS and Junos OS Evolved: Receipt of a specific malformed BGP update causes the session to reset

Noroxi assessment

Priority: Monitor (action score 34/100)

  • 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: 0.49% (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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Juniper Networks Junos OS 21.4R3-S8, 22.2R3-S4, 22.3R3-S3; Juniper Networks Junos OS Evolved 21.4R3-S8-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Juniper Networks Junos OS 21.4R3-S8, 22.2R3-S4, 22.3R3-S3; Juniper Networks Junos OS Evolved 21.4R3-S8-EVO, 22.2R3-S4-EVO, 22.3R3-S3-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 Handling of Exceptional Conditions vulnerability in the Routing Protocol Daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an attacker sending a specific malformed BGP update message to cause the session to reset, resulting in a Denial of Service (DoS). Continued receipt and processing of these malformed BGP update messages will create a sustained Denial of Service (DoS) condition. Upon receipt of a BGP update message over an established BGP session containing a specifically malformed tunnel encapsulation attribute, when segment routing is enabled, internal processing of the malformed attributes within the update results in improper parsing of remaining attributes, leading to session reset: BGP SEND Notification code 3 (Update Message Error) subcode 1 (invalid attribute list) Only systems with segment routing enabled are vulnerable to this issue. This issue affects eBGP and iBGP, in both IPv4 and IPv6 implementations, and requires a remote attacker to have at least one established BGP session. This issue affects: Junos OS: * All versions before 21.4R3-S8, * from 22.2 before 22.2R3-S4, * from 22.3 before 22.3R3-S3, * from 22.4 before 22.4R3-S3, * from 23.2 before 23.2R2-S1, * from 23.4 before 23.4R1-S2, 23.4R2. Junos OS Evolved:  * All versions before 21.4R3-S8-EVO, * from 22.2-EVO before 22.2R3-S4-EVO, * from 22.3-EVO before 22.3R3-S3-EVO, * from 22.4-EVO before 22.4R3-S3-EVO, * from 23.2-EVO before 23.2R2-S1-EVO, * from 23.4-EVO before 23.4R1-S2-EVO, 23.4R2-EVO.

HighCVSS 8.7 · v4.0—No exploit Fix available
Published
Jul 10, 2024
Updated
Jun 17, 2026
EPSS
0.4% · 43th percentile

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · juniper
7.5
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:3.1/AV:N/AC:L/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-2024-39555

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
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 junosbefore 21.4
  • juniper junos21.4
  • juniper junos22.2
  • juniper junos22.3
  • juniper junos22.4
  • juniper junos23.2
  • juniper junos23.4
  • juniper junos os evolvedbefore 21.4
  • juniper junos os evolved21.4
  • juniper junos os evolved22.2
  • juniper junos os evolved22.3
  • juniper junos os evolved22.4
  • juniper junos os evolved23.2
  • juniper junos os evolved23.4

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

    • before 21.4R3-S8affected · semver
    • 22.2 and later · before 22.2R3-S4affected · semver
    • 22.3 and later · before 22.3R3-S3affected · semver
    • 22.4 and later · before 22.4R3-S3affected · semver
    • 23.2 and later · before 23.2R2-S1affected · semver
    • 23.4 and later · before 23.4R1-S2, 23.4R2affected · semver

  • Juniper Networks Junos OS Evolved

    • before 21.4R3-S8-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 22.4R3-S3-EVOaffected · semver
    • 23.2-EVO and later · before 23.2R2-S1-EVOaffected · semver
    • 23.4-EVO and later · before 23.4R1-S2-EVO, 23.4R2-EVOaffected · semver

Same product

juniper: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-36845Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variableKEV
    98Now
  • CVE-2023-36846Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV
    79This week
  • CVE-2023-36844Junos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variablesKEV
    78This week

Published before and after this one in the same product

  • ← EarlierCVE-2024-39518Jul 10, 2024 · Junos OS: MX240, MX480, MX960 platforms using MPC10E: Memory leak will be observed when subscribed to a specific subscription on Junos Telemetry Interface
    34Monitor
  • ← EarlierCVE-2024-39554Jul 10, 2024 · Junos OS and Junos OS Evolved: BGP multipath incremental calculation is resulting in an rpd crash
    32Monitor
  • Later →CVE-2024-39556Jul 10, 2024 · Junos OS and Junos OS Evolved: Loading a malicious certificate from the CLI may result in a stack-based overflow
    28Monitor

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 OS21.4R3-S8Vendor (CNA)
Juniper Networks Junos OS22.2R3-S4Vendor (CNA)
Juniper Networks Junos OS22.3R3-S3Vendor (CNA)
Juniper Networks Junos OS22.4R3-S3Vendor (CNA)
Juniper Networks Junos OS23.2R2-S1Vendor (CNA)
Juniper Networks Junos OS23.4R1-S2, 23.4R2Vendor (CNA)
Juniper Networks Junos OS Evolved21.4R3-S8-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.2R3-S4-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.3R3-S3-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.4R3-S3-EVOVendor (CNA)
Juniper Networks Junos OS Evolved23.2R2-S1-EVOVendor (CNA)
Juniper Networks Junos OS Evolved23.4R1-S2-EVO, 23.4R2-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-2024-395521 days apartJunos OS and Junos OS Evolved: Malformed BGP UPDATE causes RPD crash
    34Monitor
  • CVE-2024-3038289 days apartJunos OS and Junos OS Evolved: RPD crash when CoS-based forwarding (CBF) policy is configured
    34Monitor
  • CVE-2024-3952591 days apartJunos OS and Junos OS Evolved: When BGP traceoptions is enabled, receipt of specially crafted BGP packet causes RPD crash
    34Monitor
  • CVE-2024-4749193 days apartJunos OS and Junos OS Evolved: Receipt of a specific malformed BGP path attribute leads to an RPD crash
    32Monitor
  • CVE-2025-52948366 days apartJunos OS: Specific unknown traffic pattern causes FPC and system to crash when packet capturing is enabled
    32Monitor
  • CVE-2023-44186273 days apartJunos OS and Junos OS Evolved: RPD crash when attempting to send a very long AS PATH to a non-4-byte-AS capable BGP neighbor
    30Monitor

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-755 · Improper Handling of Exceptional Conditions

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/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