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CVE-2023-36843· NVD / CVE Program· CNA juniper

Junos OS: SRX Series: The PFE will crash on receiving malformed SSL traffic when Sky ATP is enabled

An Improper Handling of Inconsistent Special Elements vulnerability in the Junos Services Framework (jsf) module of Juniper Networks Junos OS allows an unauthenticated network based attacker to cause a crash in the Packet Forwarding Engine (pfe) and thereby resulting in a Denial of Service (DoS). Upon receiving malformed SSL traffic, the PFE crashes. A manual restart will be needed to recover the device. This issue only affects devices with Juniper Networks Advanced Threat Prevention (ATP) Cloud enabled with Encrypted Traffic Insights (configured via ‘security-metadata-streaming policy’). This issue affects Juniper Networks Junos OS: * All versions prior to 20.4R3-S8, 20.4R3-S9; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2-S1, 22.4R3;

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Oct 12, 2023
Updated
Jun 17, 2026
EPSS
0.5% · 44th percentile
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Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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.

Noroxi analysis

No Noroxi analysis for this record yet

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Affected systems

VendorProduct
juniperjunos

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 junos21.1
  • juniper junos21.2
  • juniper junos21.3
  • juniper junos21.4
  • juniper junos22.1
  • juniper junos22.2
  • juniper junos22.3
  • juniper junos22.4

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
    • 21.1R1 and later · before 21.1*affected · 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-S5affected · semver
    • 22.1 and later · before 22.1R3-S4affected · semver
    • 22.2 and later · before 22.2R3-S2affected · semver
    • 22.3 and later · before 22.3R2-S2, 22.3R3affected · semver
    • 22.4 and later · before 22.4R2-S1, 22.4R3affected · 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
  • CVE-2023-36847Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV
    76This week
  • CVE-2020-1631Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) servicesKEV
    70This week
  • CVE-2025-21590Junos OS: An local attacker with shell access can execute arbitrary codeKEV
    57Plan

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 OS21.1*Vendor (CNA)
Juniper Networks Junos OS21.2R3-S6Vendor (CNA)
Juniper Networks Junos OS21.3R3-S5Vendor (CNA)
Juniper Networks Junos OS21.4R3-S5Vendor (CNA)
Juniper Networks Junos OS22.1R3-S4Vendor (CNA)
Juniper Networks Junos OS22.2R3-S2Vendor (CNA)
Juniper Networks Junos OS22.3R2-S2, 22.3R3Vendor (CNA)
Juniper Networks Junos OS22.4R2-S1, 22.4R3Vendor (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.

EPSS, last 120 days

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 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.

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-168 · Improper Handling of Inconsistent Special Elements

CVSS vector

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

nvd-primary

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