CVE Vulnerabilities


Out-of-bounds Write

Published: Jan 12, 2024 | Modified: Jan 18, 2024
CVSS 3.x
CVSS 2.x

A Heap-based Buffer Overflow vulnerability in the Network Services Daemon (NSD) of Juniper Networks Junos OS allows authenticated, low privileged, local attacker to cause a Denial of Service (DoS).

On an SRX 5000 Series device, when executing a specific command repeatedly, memory is corrupted, which leads to a Flow Processing Daemon (flowd) crash.

The NSD process has to be restarted to restore services.

If this issue occurs, it can be checked with the following command:

user@host> request security policies check The following log message can also be observed:

Error: policies are out of sync for PFE node.fpc.pic. This issue affects:

Juniper Networks Junos OS on SRX 5000 Series

  • All versions earlier than 20.4R3-S6;
  • 21.1 versions earlier than 21.1R3-S5;
  • 21.2 versions earlier than 21.2R3-S4;
  • 21.3 versions earlier than 21.3R3-S3;
  • 21.4 versions earlier than 21.4R3-S3;
  • 22.1 versions earlier than 22.1R3-S1;
  • 22.2 versions earlier than 22.2R3;
  • 22.3 versions earlier than 22.3R2.


The product writes data past the end, or before the beginning, of the intended buffer.

Affected Software

Name Vendor Start Version End Version
Junos Juniper * 20.4 (excluding)
Junos Juniper 20.4 (including) 20.4 (including)
Junos Juniper 20.4-r1 (including) 20.4-r1 (including)
Junos Juniper 20.4-r1-s1 (including) 20.4-r1-s1 (including)
Junos Juniper 20.4-r2 (including) 20.4-r2 (including)
Junos Juniper 20.4-r2-s1 (including) 20.4-r2-s1 (including)
Junos Juniper 20.4-r2-s2 (including) 20.4-r2-s2 (including)
Junos Juniper 20.4-r3 (including) 20.4-r3 (including)
Junos Juniper 20.4-r3-s1 (including) 20.4-r3-s1 (including)
Junos Juniper 20.4-r3-s2 (including) 20.4-r3-s2 (including)
Junos Juniper 20.4-r3-s3 (including) 20.4-r3-s3 (including)
Junos Juniper 20.4-r3-s4 (including) 20.4-r3-s4 (including)
Junos Juniper 20.4-r3-s5 (including) 20.4-r3-s5 (including)
Junos Juniper 21.1 (including) 21.1 (including)
Junos Juniper 21.1-r1 (including) 21.1-r1 (including)
Junos Juniper 21.1-r1-s1 (including) 21.1-r1-s1 (including)
Junos Juniper 21.1-r2 (including) 21.1-r2 (including)
Junos Juniper 21.1-r2-s1 (including) 21.1-r2-s1 (including)
Junos Juniper 21.1-r2-s2 (including) 21.1-r2-s2 (including)
Junos Juniper 21.1-r3 (including) 21.1-r3 (including)
Junos Juniper 21.1-r3-s1 (including) 21.1-r3-s1 (including)
Junos Juniper 21.1-r3-s2 (including) 21.1-r3-s2 (including)
Junos Juniper 21.1-r3-s3 (including) 21.1-r3-s3 (including)
Junos Juniper 21.1-r3-s4 (including) 21.1-r3-s4 (including)
Junos Juniper 21.2 (including) 21.2 (including)
Junos Juniper 21.2-r1 (including) 21.2-r1 (including)
Junos Juniper 21.2-r1-s1 (including) 21.2-r1-s1 (including)
Junos Juniper 21.2-r1-s2 (including) 21.2-r1-s2 (including)
Junos Juniper 21.2-r2 (including) 21.2-r2 (including)
Junos Juniper 21.2-r2-s1 (including) 21.2-r2-s1 (including)
Junos Juniper 21.2-r2-s2 (including) 21.2-r2-s2 (including)
Junos Juniper 21.2-r3 (including) 21.2-r3 (including)
Junos Juniper 21.2-r3-s1 (including) 21.2-r3-s1 (including)
Junos Juniper 21.2-r3-s2 (including) 21.2-r3-s2 (including)
Junos Juniper 21.2-r3-s3 (including) 21.2-r3-s3 (including)
Junos Juniper 21.3 (including) 21.3 (including)
Junos Juniper 21.3-r1 (including) 21.3-r1 (including)
Junos Juniper 21.3-r1-s1 (including) 21.3-r1-s1 (including)
Junos Juniper 21.3-r1-s2 (including) 21.3-r1-s2 (including)
Junos Juniper 21.3-r2 (including) 21.3-r2 (including)
Junos Juniper 21.3-r2-s1 (including) 21.3-r2-s1 (including)
Junos Juniper 21.3-r2-s2 (including) 21.3-r2-s2 (including)
Junos Juniper 21.3-r3 (including) 21.3-r3 (including)
Junos Juniper 21.3-r3-s1 (including) 21.3-r3-s1 (including)
Junos Juniper 21.3-r3-s2 (including) 21.3-r3-s2 (including)
Junos Juniper 21.4 (including) 21.4 (including)
Junos Juniper 21.4-r1 (including) 21.4-r1 (including)
Junos Juniper 21.4-r1-s1 (including) 21.4-r1-s1 (including)
Junos Juniper 21.4-r1-s2 (including) 21.4-r1-s2 (including)
Junos Juniper 21.4-r2 (including) 21.4-r2 (including)
Junos Juniper 21.4-r2-s1 (including) 21.4-r2-s1 (including)
Junos Juniper 21.4-r2-s2 (including) 21.4-r2-s2 (including)
Junos Juniper 21.4-r3 (including) 21.4-r3 (including)
Junos Juniper 21.4-r3-s1 (including) 21.4-r3-s1 (including)
Junos Juniper 21.4-r3-s2 (including) 21.4-r3-s2 (including)
Junos Juniper 22.1 (including) 22.1 (including)
Junos Juniper 22.1-r1 (including) 22.1-r1 (including)
Junos Juniper 22.1-r1-s1 (including) 22.1-r1-s1 (including)
Junos Juniper 22.1-r1-s2 (including) 22.1-r1-s2 (including)
Junos Juniper 22.1-r2 (including) 22.1-r2 (including)
Junos Juniper 22.1-r2-s1 (including) 22.1-r2-s1 (including)
Junos Juniper 22.1-r2-s2 (including) 22.1-r2-s2 (including)
Junos Juniper 22.1-r3 (including) 22.1-r3 (including)
Junos Juniper 22.2 (including) 22.2 (including)
Junos Juniper 22.2-r1 (including) 22.2-r1 (including)
Junos Juniper 22.2-r1-s1 (including) 22.2-r1-s1 (including)
Junos Juniper 22.2-r1-s2 (including) 22.2-r1-s2 (including)
Junos Juniper 22.2-r2 (including) 22.2-r2 (including)
Junos Juniper 22.2-r2-s1 (including) 22.2-r2-s1 (including)
Junos Juniper 22.2-r2-s2 (including) 22.2-r2-s2 (including)
Junos Juniper 22.3 (including) 22.3 (including)
Junos Juniper 22.3-r1 (including) 22.3-r1 (including)
Junos Juniper 22.3-r1-s1 (including) 22.3-r1-s1 (including)
Junos Juniper 22.3-r1-s2 (including) 22.3-r1-s2 (including)

Potential Mitigations

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

  • For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.

  • Be wary that a language’s interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

  • Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.

  • D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

  • Consider adhering to the following rules when allocating and managing an application’s memory:

  • Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.

  • Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.

  • For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.

  • For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].