Improper check for unusual conditions in Juniper Junos OS
Priority LOW 30CWE-754Published · Updated
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX and QFX Series devices allow an unauthenticated, adjacent attacker to cause a complete Denial of Service (DoS). On EX4k, and QFX5k platforms configured as service-provider edge devices, if L2PT is enabled on the UNI and VSTP is enabled on NNI in VXLAN scenarios, receiving VSTP BPDUs on UNI leads to packet buffer allocation failures, resulting in the device to not pass traffic anymore until it is manually recovered with a restart.This issue affects Junos OS: * 24.4 releases before 24.4R2, * 25.2 releases before 25.2R1-S1, 25.2R2. This issue does not affect Junos OS releases before 24.4R1.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00173 6th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 24.4R2, 25.2R1-S1, 25.2R2
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Juniper | Junos OS | 24.4 to before 24.4R2; 25.2 to before 25.2R1-S1, 25.2R2 | 24.4R2, 25.2R1-S1, 25.2R2 | Patch available | CNA |
- Junos OS VendorJuniper Affected 24.4 to before 24.4R2; 25.2 to before 25.2R1-S1, 25.2R2 Fixed in 24.4R2, 25.2R1-S1, 25.2R2 Patch available CNA
CPE configurations NVD · 25
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* | 24.4 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* | 24.4 r1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* | 24.4 r1-s2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* | 24.4 r1-s3 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* | 25.2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* | 25.2 r1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:* | 25.2 r2 | Vulnerable | Juniper |
| cpe:2.3:h:juniper:ex4000:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4100-f:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
- cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* Versions 24.4 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* Versions 24.4 r1-s3 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* Versions 25.2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* Versions 25.2 r1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:* Versions 25.2 r2 Vulnerable ·Juniper
- cpe:2.3:h:juniper:ex4000:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4100-f:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
Show 15 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:h:juniper:ex4100-h:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4300:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4400:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4600:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4650:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5110:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5120:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5130:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5200:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5210:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5220:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5230-64cd:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5240:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5241:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:qfx5700:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
- cpe:2.3:h:juniper:ex4100-h:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4300:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4400:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4600:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4650:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5110:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5120:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5130:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5200:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5210:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5220:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5230-64cd:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5240:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5241:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:qfx5700:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
Remediation
- Fix · CNA Junos OS (Juniper Networks) Fixed in 24.4R2, 25.2R1-S1, 25.2R2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-33781
- 2026-10-03 Alias added: GHSA-gv4f-m3jw-j3h9
References
Advisory 1
More Juniper Junos vulnerabilities
- TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
- TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
- TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
- TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
- TI-2023-18644 Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files KEVCVSS 3.1MEDIUM 5.3
- TI-2023-18640 Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files KEVCVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-33781 · CVE Program
- CVE-2026-33781 · NVD
- FIRST EPSS
- GHSA-gv4f-m3jw-j3h9 · GitHub Advisory Database · CC BY 4.0
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