CVE-2025-52948: Juniper Networks Junos OS · Improper Handling of Exceptional Conditions
Affects Juniper Networks Junos OSSource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Juniper Networks Junos OS | Affected
| Fixed in– |
AI-suggested
To mitigate this vulnerability, European organizations should prioritize upgrading affected Junos OS devices to the fixed versions specified by Juniper Networks (e.g., 21.2R3-S9 and later patched releases). Until patches are applied, organizations should consider disabling packet capturing features on Junos devices where feasible, as the vulnerability is more likely to be triggered when packet capture is enabled. Network administrators should monitor device logs and system behavior for signs of instability or crashes related to BPF processing. Implementing network segmentation and limiting exposure of Junos devices to untrusted networks can reduce the attack surface. Additionally, organizations should maintain robust incident response plans to quickly address any unexpected device restarts. Regularly reviewing Juniper security advisories and subscribing to vendor notifications will help ensure timely awareness of patches and related updates.
Description
An Improper Handling of Exceptional Conditions vulnerability in Berkeley Packet Filter (BPF) processing of Juniper Networks Junos OS allows an attacker, in rare cases, sending specific, unknown traffic patterns to cause the FPC and system to crash and restart. BPF provides a raw interface to data link layers in a protocol independent fashion. Internally within the Junos kernel, due to a rare timing issue (race condition), when a BPF instance is cloned, the newly created interface causes an internal structure leakage, leading to a system crash. The precise content and timing of the traffic patterns is indeterminate, but has been seen in a lab environment multiple times. This issue is more likely to occur when packet capturing is enabled. See required configuration below. This issue affects Junos OS: * all versions before 21.2R3-S9, * from 21.4 before 21.4R3-S10, * from 22.2 before 22.2R3-S6, * from 22.4 before 22.4R3-S7, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2-S3, * from 24.2 before 24.2R1-S1, 24.2R2.