Junos OS Evolved: When MAC learning happens, and an interface gets flapped, the PFE crashes
A NULL Pointer Dereference vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). When Layer 2 traffic is sent through a logical interface, MAC learning happens. If during this process, the interface flaps, an Advanced Forwarding Toolkit manager (evo-aftmand-bt) core is observed. This leads to a PFE restart. The crash reoccurs if the same sequence of events happens, which will lead to a sustained DoS condition. This issue affects Juniper Networks Junos OS Evolved 23.2-EVO versions earlier than 23.2R1-S1-EVO, 23.2R2-EVO.
- Published
- Apr 12, 2024
- Updated
- Jun 17, 2026
- EPSS
- 0.3% · 18th percentile
- CWE
- CWE-476
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Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 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
- 6.5
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:A/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.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| juniper | junos os evolved | cpe:2.3:o:juniper:junos_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 evolved23.2
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
- 23.2-EVO and later · before 23.2R1-S1-EVO, 23.2R2-EVOaffected · semver
Same product
juniper: all recordsOther 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 root42Plan
- CVE-2023-28983Junos OS Evolved: Shell Injection vulnerability in the gNOI server35Monitor
- CVE-2022-22239Junos OS Evolved: The ssh CLI command always runs as root which can lead to privilege escalation35Monitor
- CVE-2026-33788Junos OS Evolved: Local, authenticated attacker can gain privileged access to FPCs34Monitor
- CVE-2025-52954Junos OS Evolved: A low-privileged user can execute arbitrary Junos commands and modify the configuration, thereby compromising the system34Monitor
- CVE-2025-21599Junos OS Evolved: Receipt of specifically malformed IPv6 packets causes kernel memory exhaustion leading to Denial of Service34Monitor
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 Evolved | 23.2R1-S1-EVO, 23.2R2-EVO | 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.
- CVE-2024-2160292 days apartJunos OS Evolved: ACX7024, ACX7100-32C and ACX7100-48L: Traffic stops when a specific IPv4 UDP packet is received by the RE30Monitor
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-476 · NULL Pointer DereferenceCVSS vector
CVSS:4.0/AV:A/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:X/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.
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
- supportportal.juniper.net/JSA79181
- www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
Vendor advisories and official records. Exploit/PoC links are deliberately left out.