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TI-2026-17608 Aliases CVE-2026-21908GHSA-h976-gqwv-338w

Use after free in Juniper Junos OS

Priority LOW 35CWE-416Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.

Summary

A Use After Free vulnerability was identified in the 802.1X authentication daemon (dot1xd) of Juniper Networks Junos OS and Junos OS Evolved that could allow an authenticated, network-adjacent attacker flapping a port to crash the dot1xd process, leading to a Denial of Service (DoS), or potentially execute arbitrary code within the context of the process running as root. The issue is specific to the processing of a change in authorization (CoA) when a port bounce occurs. A pointer is freed but was then referenced later in the same code path. Successful exploitation is outside the attacker's direct control due to the specific timing of the two events required to execute the vulnerable code path. This issue affects systems with 802.1X authentication port-based network access control (PNAC) enabled. This issue affects: Junos OS:  * from 23.2R2-S1 before 23.2R2-S5,  * from 23.4R2 before 23.4R2-S6,  * from 24.2 before 24.2R2-S3,  * from 24.4 before 24.4R2-S1,  * from 25.2 before 25.2R1-S2, 25.2R2;  Junos OS Evolved:  * from 23.2R2-S1 before 23.2R2-S5-EVO,  * from 23.4R2 before 23.4R2-S6-EVO,  * from 24.2 before 24.2R2-S3-EVO,  * from 24.4 before 24.4R2-S1-EVO,  * from 25.2 before 25.2R1-S2-EVO, 25.2R2-EVO.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0031 24th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 23.2R2-S5, 23.4R2-S6, 24.2R2-S3 +3Junos OS Evolved (Juniper Networks): 23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S3-EVO +3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

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 OS23.2R2-S1 to before 23.2R2-S5; 23.4R2 to before 23.4R2-S6; 24.2 to before 24.2R2-S3; 24.4 to before 24.4R2-S1; 25.2 to before 25.2R1-S2, 25.2R223.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2Patch availableCNA
JuniperJunos OS Evolved23.2R2-S1 to before 23.2R2-S5-EVO; 23.4R2 to before 23.4R2-S6-EVO; 24.2 to before 24.2R2-S3-EVO; 24.4 to before 24.4R2-S1-EVO; 25.2 to before 25.2R1-S2-EVO, 25.2R2-EVO23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S3-EVO, 24.4R2-S1-EVO, 25.2R1-S2-EVO, 25.2R2-EVOPatch availableCNA
  • Junos OS VendorJuniper Affected 23.2R2-S1 to before 23.2R2-S5; 23.4R2 to before 23.4R2-S6; 24.2 to before 24.2R2-S3; 24.4 to before 24.4R2-S1; 25.2 to before 25.2R1-S2, 25.2R2 Fixed in 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2 Patch available CNA
  • Junos OS Evolved VendorJuniper Affected 23.2R2-S1 to before 23.2R2-S5-EVO; 23.4R2 to before 23.4R2-S6-EVO; 24.2 to before 24.2R2-S3-EVO; 24.4 to before 24.4R2-S1-EVO; 25.2 to before 25.2R1-S2-EVO, 25.2R2-EVO Fixed in 23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S3-EVO, 24.4R2-S1-EVO, 25.2R1-S2-EVO, 25.2R2-EVO Patch available CNA

CPE configurations NVD · 51

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:*23.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:*23.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:*23.2 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s4:*:*:*:*:*:*23.2 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:*23.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:*23.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:*23.4 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s4:*:*:*:*:*:*23.4 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s5:*:*:*:*:*:*23.4 r2-s5VulnerableJuniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:* Versions 23.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:* Versions 23.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:* Versions 23.2 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s4:*:*:*:*:*:* Versions 23.2 r2-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:* Versions 23.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:* Versions 23.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:* Versions 23.4 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s4:*:*:*:*:*:* Versions 23.4 r2-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s5:*:*:*:*:*:* Versions 23.4 r2-s5 Vulnerable ·Juniper
Show 41 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:*24.2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:*24.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:*24.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:*24.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r2:*:*:*:*:*:*24.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r2-s1:*:*:*:*:*:*24.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r2-s2:*:*:*:*:*:*24.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:*24.4VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:*24.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:*24.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:*24.4 r1-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r2:*:*:*:*:*:*24.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:*25.2VulnerableJuniper
cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:*25.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:*25.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:*25.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s1:*:*:*:*:*:*23.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s2:*:*:*:*:*:*23.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s3:*:*:*:*:*:*23.2 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s4:*:*:*:*:*:*23.2 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s1:*:*:*:*:*:*23.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s2:*:*:*:*:*:*23.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s3:*:*:*:*:*:*23.4 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s4:*:*:*:*:*:*23.4 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s5:*:*:*:*:*:*23.4 r2-s5VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:-:*:*:*:*:*:*24.2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r1:*:*:*:*:*:*24.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r1-s2:*:*:*:*:*:*24.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r2:*:*:*:*:*:*24.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r2-s1:*:*:*:*:*:*24.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r2-s2:*:*:*:*:*:*24.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:-:*:*:*:*:*:*24.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r1:*:*:*:*:*:*24.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r1-s2:*:*:*:*:*:*24.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r1-s3:*:*:*:*:*:*24.4 r1-s3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r2:*:*:*:*:*:*24.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:25.2:-:*:*:*:*:*:*25.2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:25.2:r1:*:*:*:*:*:*25.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:25.2:r1-s1:*:*:*:*:*:*25.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:25.2:r2:*:*:*:*:*:*25.2 r2VulnerableJuniper
  • cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:* Versions 24.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:* Versions 24.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:* Versions 24.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:* Versions 24.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r2:*:*:*:*:*:* Versions 24.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r2-s1:*:*:*:*:*:* Versions 24.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r2-s2:*:*:*:*:*:* Versions 24.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* Versions 24.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* Versions 24.4 r1-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r2:*:*:*:*:*:* Versions 24.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* Versions 25.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* Versions 25.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:* Versions 25.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:* Versions 25.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s1:*:*:*:*:*:* Versions 23.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s2:*:*:*:*:*:* Versions 23.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s3:*:*:*:*:*:* Versions 23.2 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r2-s4:*:*:*:*:*:* Versions 23.2 r2-s4 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:23.4:r2-s1:*:*:*:*:*:* Versions 23.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s2:*:*:*:*:*:* Versions 23.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s3:*:*:*:*:*:* Versions 23.4 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s4:*:*:*:*:*:* Versions 23.4 r2-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s5:*:*:*:*:*:* Versions 23.4 r2-s5 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:-:*:*:*:*:*:* Versions 24.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r1:*:*:*:*:*:* Versions 24.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r1-s2:*:*:*:*:*:* Versions 24.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r2:*:*:*:*:*:* Versions 24.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r2-s1:*:*:*:*:*:* Versions 24.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r2-s2:*:*:*:*:*:* Versions 24.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:-:*:*:*:*:*:* Versions 24.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r1-s3:*:*:*:*:*:* Versions 24.4 r1-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r2:*:*:*:*:*:* Versions 24.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:25.2:-:*:*:*:*:*:* Versions 25.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:25.2:r1:*:*:*:*:*:* Versions 25.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:25.2:r1-s1:*:*:*:*:*:* Versions 25.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:25.2:r2:*:*:*:*:*:* Versions 25.2 r2 Vulnerable ·Juniper

Remediation

  • Fix · CNA Junos OS (Juniper Networks) Fixed in 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2
  • Fix · CNA Junos OS Evolved (Juniper Networks) Fixed in 23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S3-EVO, 24.4R2-S1-EVO, 25.2R1-S2-EVO, 25.2R2-EVO

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21908
  2. 2026-10-03 Alias added: GHSA-h976-gqwv-338w

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