Junos OS: ACX Series: When 'hot-standby' mode is configured for an L2 circuit, interface flap causes the FEB to crash
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 Handling of Exceptional Conditions vulnerability in route processing of Juniper Networks Junos OS on specific end-of-life (EOL) ACX Series platforms allows an attacker to crash the Forwarding Engine Board (FEB) by flapping an interface, leading to a Denial of Service (DoS). On ACX1000, ACX1100, ACX2000, ACX2100, ACX2200, ACX4000, ACX5048, and ACX5096 devices, FEB0 will crash when the primary path port of the L2 circuit IGP (Interior Gateway Protocol) on the local device goes down. This issue is seen only when 'hot-standby' mode is configured for the L2 circuit. This issue affects Junos OS on ACX1000, ACX1100, ACX2000, ACX2100, ACX2200, ACX4000, ACX5048, and ACX5096: * all versions before 21.2R3-S9.
Why it matters now
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 | before 21.2R3-S9 | 21.2R3-S9 | Patch available | CNA |
- Junos OS VendorJuniper Affected before 21.2R3-S9 Fixed in 21.2R3-S9 Patch available CNA
CPE configurations NVD · 25
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | before 21.2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:-:*:*:*:*:*:* | 21.2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r1:*:*:*:*:*:* | 21.2 r1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r1-s1:*:*:*:*:*:* | 21.2 r1-s1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r1-s2:*:*:*:*:*:* | 21.2 r1-s2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r2:*:*:*:*:*:* | 21.2 r2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r2-s1:*:*:*:*:*:* | 21.2 r2-s1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r2-s2:*:*:*:*:*:* | 21.2 r2-s2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3:*:*:*:*:*:* | 21.2 r3 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s1:*:*:*:*:*:* | 21.2 r3-s1 | Vulnerable | Juniper |
- cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* Versions before 21.2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:-:*:*:*:*:*:* Versions 21.2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r1:*:*:*:*:*:* Versions 21.2 r1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r1-s1:*:*:*:*:*:* Versions 21.2 r1-s1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r1-s2:*:*:*:*:*:* Versions 21.2 r1-s2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r2:*:*:*:*:*:* Versions 21.2 r2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r2-s1:*:*:*:*:*:* Versions 21.2 r2-s1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r2-s2:*:*:*:*:*:* Versions 21.2 r2-s2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3:*:*:*:*:*:* Versions 21.2 r3 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s1:*:*:*:*:*:* Versions 21.2 r3-s1 Vulnerable ·Juniper
Show 15 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:juniper:junos:21.2:r3-s2:*:*:*:*:*:* | 21.2 r3-s2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s3:*:*:*:*:*:* | 21.2 r3-s3 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s4:*:*:*:*:*:* | 21.2 r3-s4 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s5:*:*:*:*:*:* | 21.2 r3-s5 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s6:*:*:*:*:*:* | 21.2 r3-s6 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s7:*:*:*:*:*:* | 21.2 r3-s7 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:21.2:r3-s8:*:*:*:*:*:* | 21.2 r3-s8 | Vulnerable | Juniper |
| cpe:2.3:h:juniper:acx1000:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx1100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx2000:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx2100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx2200:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx4000:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx5048:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:acx5096:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
- cpe:2.3:o:juniper:junos:21.2:r3-s2:*:*:*:*:*:* Versions 21.2 r3-s2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s3:*:*:*:*:*:* Versions 21.2 r3-s3 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s4:*:*:*:*:*:* Versions 21.2 r3-s4 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s5:*:*:*:*:*:* Versions 21.2 r3-s5 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s6:*:*:*:*:*:* Versions 21.2 r3-s6 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s7:*:*:*:*:*:* Versions 21.2 r3-s7 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:21.2:r3-s8:*:*:*:*:*:* Versions 21.2 r3-s8 Vulnerable ·Juniper
- cpe:2.3:h:juniper:acx1000:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx1100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx2000:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx2100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx2200:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx4000:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx5048:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:acx5096:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
Remediation
- Fix · CNA Junos OS (Juniper Networks) Fixed in 21.2R3-S9
Timeline
- 2026-10-02 Threatist record created from CVE-2025-52947
- 2026-10-03 Alias added: GHSA-xw3x-vr3j-962f
References
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-2025-52947 · CVE Program
- CVE-2025-52947 · NVD
- FIRST EPSS
- GHSA-xw3x-vr3j-962f · GitHub Advisory Database · CC BY 4.0
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