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NVD / CVE Program· CNA juniper

CVE-2025-21597: Junos OS and Junos OS Evolved: When BGP rib-sharding and update-threading are configured and a peer flaps, an rpd core is observed

Noroxi assessment

Priority: Monitor (action score 24/100)

  • 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: 0.25% (FIRST EPSS).
  • Someone on the same network segment 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 20.4R3-S8, 21.2R3-S6, 21.3R3-S5; Juniper Networks Junos OS Evolved 21.2R3-S6-EVO, 21.3R3-S5-EVO, 21.4R3-S4-EVO.

Low priority for now. Upgrade to Juniper Networks Junos OS 20.4R3-S8, 21.2R3-S6, 21.3R3-S5; Juniper Networks Junos OS Evolved 21.2R3-S6-EVO, 21.3R3-S5-EVO, 21.4R3-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 routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, logically adjacent BGP peer to cause Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, when BGP rib-sharding and update-threading are configured, and a BGP peer flap is done with specific timing, rpd crashes and restarts. Continuous peer flapping at specific time intervals will result in a sustained Denial of Service (DoS) condition. This issue affects eBGP and iBGP, in both IPv4 and IPv6 implementations. This issue requires a remote attacker to have at least one established BGP session. The issue can occur with or without logical-systems enabled. This issue affects: Junos OS: * All versions before 20.4R3-S8, * 21.2 versions before 21.2R3-S6, * 21.3 versions before 21.3R3-S5, * 21.4 versions before 21.4R3-S4, * 22.1 versions before 22.1R3-S3, * 22.2 versions before 22.2R3-S1, * 22.3 versions before 22.3R3, * 22.4 versions before 22.4R3. Junos OS Evolved: * All versions before 21.2R3-S6-EVO, * 21.3-EVO versions before 21.3R3-S5-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.1-EVO versions before 22.1R3-S3-EVO, * 22.2-EVO versions before :22.2R3-S1-EVO, * 22.3-EVO versions before 22.3R3-EVO, * 22.4-EVO versions before 22.4R3-EVO.

MediumCVSS 6.0 · v4.0—No exploit Fix available
Published
Apr 9, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 16th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · juniper
5.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:3.1/AV:A/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-2025-21597

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 20.4
  • juniper junos20.4
  • juniper junos21.2
  • juniper junos21.3
  • juniper junos21.4
  • juniper junos22.1
  • juniper junos22.2
  • juniper junos22.3
  • juniper junos22.4
  • juniper junos os evolvedbefore 21.2
  • juniper junos os evolved21.2
  • juniper junos os evolved21.3
  • 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

    • before 20.4R3-S8affected · semver
    • 21.2 and later · before 21.2R3-S6affected · semver
    • 21.3 and later · before 21.3R3-S5affected · semver
    • 21.4 and later · before 21.4R3-S4affected · semver
    • 22.1 and later · before 22.1R3-S3affected · semver
    • 22.2 and later · before 22.2R3-S1affected · semver
    • 22.3 and later · before 22.3R3affected · semver
    • 22.4 and later · before 22.4R3affected · semver

  • Juniper Networks Junos OS Evolved

    • before 21.2R3-S6-EVOaffected · semver
    • 21.3-EVO and later · before 21.3R3-S5-EVOaffected · semver
    • 21.4-EVO and later · before 21.4R3-S4-EVOaffected · semver
    • 22.1-EVO and later · before 22.1R3-S3-EVOaffected · semver
    • 22.2-EVO and later · before 22.2R3-S1-EVOaffected · semver
    • 22.3-EVO and later · before 22.3R3-EVOaffected · semver
    • 22.4-EVO and later · before 22.4R3-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-2025-21594Apr 9, 2025 · Junos OS: MX Series: In DS-lite and NAT scenario receipt of crafted IPv6 traffic causes port block
    34Monitor
  • ← EarlierCVE-2025-21595Apr 9, 2025 · Junos OS and Junos OS Evolved: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash
    28Monitor
  • Later →CVE-2025-21601Apr 9, 2025 · Junos OS: SRX and EX Series, MX240, MX480, MX960, QFX5120 Series: When web management is enabled for specific services an attacker may cause a CPU spike by send
    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 OS20.4R3-S8Vendor (CNA)
Juniper Networks Junos OS21.2R3-S6Vendor (CNA)
Juniper Networks Junos OS21.3R3-S5Vendor (CNA)
Juniper Networks Junos OS21.4R3-S4Vendor (CNA)
Juniper Networks Junos OS22.1R3-S3Vendor (CNA)
Juniper Networks Junos OS22.2R3-S1Vendor (CNA)
Juniper Networks Junos OS22.3R3Vendor (CNA)
Juniper Networks Junos OS22.4R3Vendor (CNA)
Juniper Networks Junos OS Evolved21.2R3-S6-EVOVendor (CNA)
Juniper Networks Junos OS Evolved21.3R3-S5-EVOVendor (CNA)
Juniper Networks Junos OS Evolved21.4R3-S4-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.1R3-S3-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.2R3-S1-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.3R3-EVOVendor (CNA)
Juniper Networks Junos OS Evolved22.4R3-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-2025-215940 days apartJunos OS: MX Series: In DS-lite and NAT scenario receipt of crafted IPv6 traffic causes port block
    34Monitor
  • CVE-2025-306600 days apartJunos OS: MX Series: Decapsulation of specific GRE packets leads to PFE reset
    34Monitor
  • CVE-2025-5298193 days apartJunos OS: SRX Series: Sequence of specific PIM packets causes a flowd crash
    34Monitor
  • CVE-2024-47499180 days apartJunos OS and Junos OS Evolved: In a BMP scenario receipt of a malformed AS PATH attribute can cause an RPD crash
    34Monitor
  • CVE-2025-60004183 days apartJunos OS and Junos OS Evolved: Specific BGP EVPN update message causes rpd crash
    34Monitor
  • CVE-2024-39530272 days apartJunos OS: Attempting to access specific sensors on platforms not supporting these will lead to a chassisd crash
    34Monitor

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).

Technical details

Attack conditions

  • Someone on the same network segment 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
Adjacent
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:A/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