Read the docs
TI-2026-17609 Aliases CVE-2026-21909GHSA-cf3w-5gm7-wvp9

Junos OS and Junos OS Evolved: Receipt of specific IS-IS update packet causes memory leak leading to RPD crash

Priority LOW 31CWE-401Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-401.

Summary

A Missing Release of Memory after Effective Lifetime vulnerability in the routing protocol daemon (rpd) Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated attacker controlling an adjacent IS-IS neighbor to send a specific update packet causing a memory leak. Continued receipt and processing of these packets will exhaust all available memory, crashing rpd and creating a Denial of Service (DoS) condition. Memory usage can be monitored through the use of the 'show task memory detail' command. For example: user@junos> show task memory detail | match ted-infra   TED-INFRA-COOKIE           25   1072     28   1184     229 user@junos> show task memory detail | match ted-infra   TED-INFRA-COOKIE           31   1360     34   1472     307 This issue affects: Junos OS:  * from 23.2 before 23.2R2,  * from 23.4 before 23.4R1-S2, 23.4R2,  * from 24.1 before 24.1R2;  Junos OS Evolved:  * from 23.2 before 23.2R2-EVO,  * from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO,  * from 24.1 before 24.1R2-EVO. This issue does not affect Junos OS versions before 23.2R1 or Junos OS Evolved versions before 23.2R1-EVO.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00249 16th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 23.2R2, 23.4R1-S2, 23.4R2 +1Junos OS Evolved (Juniper Networks): 23.2R2-EVO, 23.4R1-S2-EVO, 23.4R2-EVO +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
JuniperJunos OS23.2 to before 23.2R2; 23.4 to before 23.4R1-S2, 23.4R2; 24.1 to before 24.1R223.2R2, 23.4R1-S2, 23.4R2, 24.1R2Patch availableCNA
JuniperJunos OS Evolved23.2 to before 23.2R2-EVO; 23.4 to before 23.4R1-S2-EVO, 23.4R2-EVO; 24.1 to before 24.1R2-EVO23.2R2-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.1R2-EVOPatch availableCNA
  • Junos OS VendorJuniper Affected 23.2 to before 23.2R2; 23.4 to before 23.4R1-S2, 23.4R2; 24.1 to before 24.1R2 Fixed in 23.2R2, 23.4R1-S2, 23.4R2, 24.1R2 Patch available CNA
  • Junos OS Evolved VendorJuniper Affected 23.2 to before 23.2R2-EVO; 23.4 to before 23.4R1-S2-EVO, 23.4R2-EVO; 24.1 to before 24.1R2-EVO Fixed in 23.2R2-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.1R2-EVO Patch available CNA

CPE configurations NVD · 20

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:*23.2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:*23.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:*23.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:*23.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:*23.4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.1:-:*:*:*:*:*:*24.1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.1:r1:*:*:*:*:*:*24.1 r1VulnerableJuniper
  • cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:* Versions 23.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* Versions 23.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* Versions 23.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* Versions 23.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:* Versions 23.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.1:-:*:*:*:*:*:* Versions 24.1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.1:r1:*:*:*:*:*:* Versions 24.1 r1 Vulnerable ·Juniper
Show 10 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos_os_evolved:23.2:-:*:*:*:*:*:*23.2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1:*:*:*:*:*:*23.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s1:*:*:*:*:*:*23.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s2:*:*:*:*:*:*23.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:*23.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.1:-:*:*:*:*:*:*24.1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.1:r1:*:*:*:*:*:*24.1 r1VulnerableJuniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:-:*:*:*:*:*:* Versions 23.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r1:*:*:*:*:*:* Versions 23.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s1:*:*:*:*:*:* Versions 23.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s2:*:*:*:*:*:* Versions 23.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:* Versions 23.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.1:-:*:*:*:*:*:* Versions 24.1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.1:r1:*:*:*:*:*:* Versions 24.1 r1 Vulnerable ·Juniper

Remediation

  • Fix · CNA Junos OS (Juniper Networks) Fixed in 23.2R2, 23.4R1-S2, 23.4R2, 24.1R2
  • Fix · CNA Junos OS Evolved (Juniper Networks) Fixed in 23.2R2-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.1R2-EVO

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21909
  2. 2026-10-03 Alias added: GHSA-cf3w-5gm7-wvp9

References

Advisory 2

  • TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
  • TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
  • TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
  • TI-2023-18644 Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files KEVCVSS 3.1MEDIUM 5.3
  • TI-2023-18640 Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files KEVCVSS 3.1MEDIUM 5.3
See all 792 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences