SRX Series: A remote attacker may cause a high CPU Denial of Service to the device when proxy ARP is configured.
A firewall bypass vulnerability in the proxy ARP service of Juniper Networks Junos OS allows an attacker to cause a high CPU condition leading to a Denial of Service (DoS). This issue affects only IPv4. Affected releases are Juniper Networks Junos OS: 12.1X46 versions above and including 12.1X46-D25 prior to 12.1X46-D71, 12.1X46-D73 on SRX Series; 12.3X48 versions prior to 12.3X48-D50 on SRX Series; 15.1X49 versions prior to 15.1X49-D75 on SRX Series.
- Published
- Apr 10, 2019
- Updated
- Jun 16, 2026
- EPSS
- 1.6% · 74th percentile
- CWE
- CWE-400
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.6%
CNA vs NVD score
- NVD
- 7.5
- CNA · juniper
- 7.5
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| juniper | junos | cpe:2.3:o:juniper:junos |
| juniper | srx100 | cpe:2.3:h:juniper:srx100 |
| juniper | srx110 | cpe:2.3:h:juniper:srx110 |
| juniper | srx1400 | cpe:2.3:h:juniper:srx1400 |
| juniper | srx210 | cpe:2.3:h:juniper:srx210 |
| juniper | srx220 | cpe:2.3:h:juniper:srx220 |
| juniper | srx240 | cpe:2.3:h:juniper:srx240 |
| juniper | srx3400 | cpe:2.3:h:juniper:srx3400 |
| juniper | srx3600 | cpe:2.3:h:juniper:srx3600 |
| juniper | srx5400 | cpe:2.3:h:juniper:srx5400 |
| juniper | srx550 | cpe:2.3:h:juniper:srx550 |
| juniper | srx5600 | cpe:2.3:h:juniper:srx5600 |
and 2 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- juniper junos12.1x46 and later · up to 12.1x46-d10 inclusive
- juniper junos12.1x46-d25 and later · before 12.1x46-d71
- juniper junos12.3x48 and later · before 12.3x48-d50
- juniper junos15.1x49 and later · before 15.1x49-d75
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
- 12.1X46-D25 and later · before 12.1X46*affectedfixed in 12.1X46-D71, 12.1X46-D73
- 12.3X48 and later · before 12.3X48-D50affected
- 15.1X49 and later · before 15.1X49-D75affected
Same product
juniper: all recordsOther 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 variableKEV98Now
- CVE-2023-36846Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV79This week
- CVE-2023-36844Junos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variablesKEV78This week
- CVE-2023-36847Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV76This week
- CVE-2020-1631Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) servicesKEV70This week
- CVE-2025-21590Junos OS: An local attacker with shell access can execute arbitrary codeKEV57Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Juniper Networks Junos OS | 12.1X46-D71, 12.1X46-D73 | Vendor (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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, 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.
No nightly-computed relations.
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
- 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
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-400 · Uncontrolled Resource ConsumptionCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Root cause
Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.
The bug in code
The whole CWE-400 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
function expand(node) { return node.children.map(expand);}Fixed
const MAX_DEPTH = 32;function expand(node, depth = 0) { if (depth > MAX_DEPTH) throw new Error("too deep"); return node.children.map((c) => expand(c, depth + 1));}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.