Cyber Resilience

CVE-2024-39554

Race Condition in Juniper Junos 21.1 – 21.2

Published
10 July 2024
Modified
07 February 2025
Patch / advisory
CVSS Score v4 8.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0037 29th percentile
Risk Priority 43 floored blend · peak EPSS

Summary

CVE-2024-39554 is a high-severity Race Condition (CWE-362) vulnerability in Juniper Junos. Its CVSS base score is 8.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-39 (Process Isolation) and SC-4 (Information in Shared System Resources) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to inject incremental routing updates when BGP…

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multipath is enabled, causing rpd to crash and restart, resulting in a Denial of Service (DoS). Since this is a timing issue (race condition), the successful exploitation of this vulnerability is outside the attacker's control. However, continued receipt and processing of this packet may create a sustained Denial of Service (DoS) condition. On all Junos OS and Junos OS Evolved platforms with BGP multipath enabled, a specific multipath calculation removes the original next hop from the multipath lead routes nexthop-set. When this change happens, multipath relies on certain internal timing to record the update. Under certain circumstance and with specific timing, this could result in an rpd crash. This issue only affects systems with BGP multipath enabled. This issue affects: Junos OS: * All versions of 21.1 * from 21.2 before 21.2R3-S7, * from 21.4 before 21.4R3-S6, * from 22.1 before 22.1R3-S5, * from 22.2 before 22.2R3-S3, * from 22.3 before 22.3R3-S2, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2. Junos OS Evolved: * All versions of 21.1-EVO, * All versions of 21.2-EVO, * from 21.4-EVO before 21.4R3-S6-EVO, * from 22.1-EVO before 22.1R3-S5-EVO, * from 22.2-EVO before 22.2R3-S3-EVO, * from 22.3-EVO before 22.3R3-S2-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO. Versions of Junos OS before 21.1R1 are unaffected by this vulnerability. Versions of Junos OS Evolved before 21.1R1-EVO are unaffected by this vulnerability.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-21601Same product: Juniper Junos
CVE-2026-21919Same product: Juniper Junos
CVE-2025-52949Same product: Juniper Junos
CVE-2026-33793Same product: Juniper Junos
CVE-2023-28964Same product: Juniper Junos
CVE-2025-30653Same product: Juniper Junos
CVE-2025-30651Same product: Juniper Junos
CVE-2023-4481Same product: Juniper Junos
CVE-2025-52955Same product: Juniper Junos
CVE-2026-21908Same product: Juniper Junos

Affected Assets

juniper
junos
21.2, 21.4, 22.1, 22.2, 22.3 · 21.1 — 21.2
juniper
junos os evolved
21.4, 22.1, 22.2, 22.3, 22.4 · 21.1 — 21.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V10.4.2
  • V10.4.5
  • V15.1.3
  • V15.4.1

Mitigating Controls (NIST 800-53 r5) AI

Maintaining separate execution domains for each process structurally eliminates unintended concurrent access to the same shared resources.

Preventing unintended information transfer through shared system resources directly addresses the improper concurrent modification that defines a race condition.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper synchronization primitives and concurrency testing that prevent race conditions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect race conditions, but does not prevent them at design or coding time.

prevents

Secure SDLC mandates concurrency controls and synchronization primitives that directly prevent race conditions.

prevents

Application security requirements can specify thread-safety and locking rules, but do not prescribe implementation details.

prevents

Secure architecture principles require proper synchronization and resource isolation, addressing the root cause of CWE-362.

prevents

Secure coding standards explicitly forbid unsafe concurrent access patterns and mandate atomic operations or locks.

none

Change management reduces introduction of concurrency bugs during updates, yet does not address the weakness itself.

References