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Juniper Junos OS: Stack-based buffer overflow in rpd via BGP route updates

CVE-2026-33789Critical 9.2

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Summary

A stack-based buffer overflow in the routing protocol daemon (rpd) of Junos OS and Junos OS Evolved can be triggered by crafted BGP route updates. An unauthenticated BGP peer can cause a denial of service and, according to the CVE record, potentially execute commands with root privileges. The flaw is only reachable when the BGP Monitoring Protocol (BMP) is enabled, so exposure is limited to devices with BGP sessions and BMP configured, which is more typical of carriers and data centres than of most SMEs.

Affected

  • Junos OS: 0 to < 23.2R2-S7.7; 23.4 to < 23.4R2-S8.13; 24.2 to < 24.2R2-S5.5; 24.4 to < 24.4R2-S5; 25.2 to < 25.2R2-S2; 25.4 to < 25.4R1-S3; 26.2 to < 26.2R1-S2
  • Junos OS Evolved: 0 to < 23.2R2-S7.7-EVO; 23.4 to < 23.4R2-S8.11-EVO; 24.2 to < 24.2R2-S5.6-EVO; 24.4 to < 24.4R2-S5-EVO; 25.2 to < 25.2R2-S2-EVO; 25.4 to < 25.4R1-S3-EVO; 26.2 to < 26.2R1-S2-EVO; 23.4X100; 25.2X100 to < 25.2X100-D35-EVO; 25.4X300 to < 25.4X300-D40-EVO
  • Required configuration: routing-options bmp station and protocols bgp with family inet flow

Fixed in

  • Junos OS: 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, 25.4R2, 26.2R1-S2, 26.2R2, 26.4R1 and all later releases
  • Junos OS Evolved: 23.2R2-S7.7-EVO, 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO, 25.2R2-S2-EVO, 25.2X100-D35-EVO, 25.4R1-S3-EVO, 25.4R2-EVO, 25.4X300-D40-EVO, 26.2R1-S2-EVO, 26.2R2-EVO, 26.4R1-EVO and all later releases
  • Junos OS Evolved 23.4X100: Unknown. Check JSA112187.

Workaround

  • Disable BMP, or
  • Avoid configuring 'family inet flow'

Exploitation

  • Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
  • CISA SSVC assessment: exploitation none, automatable yes, technical impact total.

Our recommendation

  • Check whether any Junos OS or Junos OS Evolved device runs BGP together with BMP or 'family inet flow'.
  • If BMP is not required, disable it as the first mitigation.
  • Otherwise, plan the update to a fixed release listed in JSA112187 and restrict which peers may form BGP sessions.
  • Monitor the Juniper advisory JSA112187 for updates.

Public exploits

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 04:26.

Original description (NVD)

A Stack-based Buffer Overflow vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated BGP peer to cause a denial of service and potential root-level command execution via crafted BGP route updates when the BGP Monitoring Protocol (BMP) is enabled.

NVD references (1)

Sources

The tracker combines official, freely usable data sources – updated continuously:

This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.

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