CVE intelligence and bounded remediation

CVE-2021-0262 — Juniper Junos security vulnerability

Medium CVSS 6.5

Through routine static code analysis of the Juniper Networks Junos OS software codebase, the Secure Development Life Cycle team identified a Use After Free vulnerability in PFE packet processing on the QFX10002-60C switching platform. Exploitation of this vulnerability may allow a logically adjacent attacker to trigger a Denial of Service (DoS). Continued exploitation of this vulnerability will sustain the Denial of Service (DoS) condition. This issue only affects QFX10002-60C devices. No other product or platform is vulnerable to this issue. This issue affects Juniper Networks Junos OS on QFX10002-60C: 19.1 version 19.1R3-S1 and later versions; 19.1 versions prior to 19.1R3-S3; 19.2 version 19.2R2 and later versions; 19.2 versions prior to 19.2R3-S1; 20.2 versions prior to 20.2R1-S2. This issue does not affect Juniper Networks Junos OS: versions prior to 19.1R3; 19.2 versions prior to 19.2R2; any version of 19.3; version 20.2R2 and later releases.

Severity
Medium
CVSS
6.5 (3.1)
Published
2021-04-22
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-416

Affected products

  • juniper / junos / 19.1
  • juniper / junos / 19.2
  • juniper / junos / 20.2

Showing 3 representative product identities from 7 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Use-after-free, double free, and expired resource use

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace ownership, references, callbacks, asynchronous tasks, and teardown paths around the affected object or resource.
  • Identify reachable inputs and timing or state transitions that can release the object while references remain.
  • Confirm affected builds, allocators, feature flags, architectures, and process privileges.

Remediate safely

  • Apply the maintained ownership or lifetime fix and rebuild all artifacts containing the affected native code.
  • Use explicit ownership, safe reference management, cancellation and join semantics, and idempotent teardown.
  • Add deterministic lifetime tests plus isolated sanitizer and concurrency coverage for shutdown and error paths.

Authoritative sources

Complete CVE record and remediation plan

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