A Use After Free vulnerability in the Routing Protocol Daemon (rdp) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker to cause Denial of Service (DoS). When a BGP session flap happens, a Use After Free of a memory location that was assigned to another object can occur, which will lead to an rpd crash. This is a race condition that is outside of the attackers control and cannot be deterministically exploited. Continued flapping of BGP sessions can create a sustained Denial of Service (DoS) condition. This issue affects Juniper Networks Junos OS: All versions prior to 18.4R2-S9, 18.4R3-S11; 19.1 versions prior to 19.1R3-S8; 19.2 version 19.2R1 and later versions; 19.3 versions prior to 19.3R3-S5; 19.4 versions prior to 19.4R2-S6, 19.4R3-S6; 20.1 version 20.1R1 and later versions; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S2; 20.4 versions prior to 20.4R3-S1; 21.1 versions prior to 21.1R3-S3; 21.2 versions prior to 21.2R2-S1, 21.2R3. Juniper Networks Junos OS Evolved All versions prior to 20.4R3-S4-EVO; 21.1-EVO versions prior to 21.1R3-S2-EVO; 21.2-EVO versions prior to 21.2R3-EVO; 21.3-EVO versions prior to 21.3R2-EVO.
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Junos | Juniper | * | 18.4 (excluding) |
| Junos | Juniper | 18.4 (including) | 18.4 (including) |
| Junos | Juniper | 18.4-r1 (including) | 18.4-r1 (including) |
| Junos | Juniper | 18.4-r1-s1 (including) | 18.4-r1-s1 (including) |
| Junos | Juniper | 18.4-r1-s2 (including) | 18.4-r1-s2 (including) |
| Junos | Juniper | 18.4-r1-s3 (including) | 18.4-r1-s3 (including) |
| Junos | Juniper | 18.4-r1-s4 (including) | 18.4-r1-s4 (including) |
| Junos | Juniper | 18.4-r1-s5 (including) | 18.4-r1-s5 (including) |
| Junos | Juniper | 18.4-r1-s6 (including) | 18.4-r1-s6 (including) |
| Junos | Juniper | 18.4-r1-s7 (including) | 18.4-r1-s7 (including) |
| Junos | Juniper | 18.4-r2 (including) | 18.4-r2 (including) |
| Junos | Juniper | 18.4-r2-s1 (including) | 18.4-r2-s1 (including) |
| Junos | Juniper | 18.4-r2-s10 (including) | 18.4-r2-s10 (including) |
| Junos | Juniper | 18.4-r2-s2 (including) | 18.4-r2-s2 (including) |
| Junos | Juniper | 18.4-r2-s3 (including) | 18.4-r2-s3 (including) |
| Junos | Juniper | 18.4-r2-s4 (including) | 18.4-r2-s4 (including) |
| Junos | Juniper | 18.4-r2-s5 (including) | 18.4-r2-s5 (including) |
| Junos | Juniper | 18.4-r2-s6 (including) | 18.4-r2-s6 (including) |
| Junos | Juniper | 18.4-r2-s7 (including) | 18.4-r2-s7 (including) |
| Junos | Juniper | 18.4-r2-s8 (including) | 18.4-r2-s8 (including) |
| Junos | Juniper | 18.4-r3-s11 (including) | 18.4-r3-s11 (including) |
| Junos | Juniper | 19.1 (including) | 19.1 (including) |
| Junos | Juniper | 19.1-r1 (including) | 19.1-r1 (including) |
| Junos | Juniper | 19.1-r1-s1 (including) | 19.1-r1-s1 (including) |
| Junos | Juniper | 19.1-r1-s2 (including) | 19.1-r1-s2 (including) |
| Junos | Juniper | 19.1-r1-s3 (including) | 19.1-r1-s3 (including) |
| Junos | Juniper | 19.1-r1-s4 (including) | 19.1-r1-s4 (including) |
| Junos | Juniper | 19.1-r1-s5 (including) | 19.1-r1-s5 (including) |
| Junos | Juniper | 19.1-r1-s6 (including) | 19.1-r1-s6 (including) |
| Junos | Juniper | 19.1-r2 (including) | 19.1-r2 (including) |
| Junos | Juniper | 19.1-r2-s1 (including) | 19.1-r2-s1 (including) |
| Junos | Juniper | 19.1-r2-s2 (including) | 19.1-r2-s2 (including) |
| Junos | Juniper | 19.1-r2-s3 (including) | 19.1-r2-s3 (including) |
| Junos | Juniper | 19.1-r3 (including) | 19.1-r3 (including) |
| Junos | Juniper | 19.1-r3-s1 (including) | 19.1-r3-s1 (including) |
| Junos | Juniper | 19.1-r3-s2 (including) | 19.1-r3-s2 (including) |
| Junos | Juniper | 19.1-r3-s3 (including) | 19.1-r3-s3 (including) |
| Junos | Juniper | 19.1-r3-s4 (including) | 19.1-r3-s4 (including) |
| Junos | Juniper | 19.1-r3-s5 (including) | 19.1-r3-s5 (including) |
| Junos | Juniper | 19.1-r3-s6 (including) | 19.1-r3-s6 (including) |
| Junos | Juniper | 19.1-r3-s7 (including) | 19.1-r3-s7 (including) |
| Junos | Juniper | 19.2 (including) | 19.2 (including) |
| Junos | Juniper | 19.2-r1 (including) | 19.2-r1 (including) |
| Junos | Juniper | 19.3 (including) | 19.3 (including) |
| Junos | Juniper | 19.3-r1 (including) | 19.3-r1 (including) |
| Junos | Juniper | 19.3-r1-s1 (including) | 19.3-r1-s1 (including) |
| Junos | Juniper | 19.3-r2 (including) | 19.3-r2 (including) |
| Junos | Juniper | 19.3-r2-s1 (including) | 19.3-r2-s1 (including) |
| Junos | Juniper | 19.3-r2-s2 (including) | 19.3-r2-s2 (including) |
| Junos | Juniper | 19.3-r2-s3 (including) | 19.3-r2-s3 (including) |
| Junos | Juniper | 19.3-r2-s4 (including) | 19.3-r2-s4 (including) |
| Junos | Juniper | 19.3-r2-s5 (including) | 19.3-r2-s5 (including) |
| Junos | Juniper | 19.3-r2-s6 (including) | 19.3-r2-s6 (including) |
| Junos | Juniper | 19.3-r3 (including) | 19.3-r3 (including) |
| Junos | Juniper | 19.3-r3-s1 (including) | 19.3-r3-s1 (including) |
| Junos | Juniper | 19.3-r3-s2 (including) | 19.3-r3-s2 (including) |
| Junos | Juniper | 19.3-r3-s3 (including) | 19.3-r3-s3 (including) |
| Junos | Juniper | 19.3-r3-s4 (including) | 19.3-r3-s4 (including) |
| Junos | Juniper | 19.4 (including) | 19.4 (including) |
| Junos | Juniper | 19.4-r1 (including) | 19.4-r1 (including) |
| Junos | Juniper | 19.4-r1-s1 (including) | 19.4-r1-s1 (including) |
| Junos | Juniper | 19.4-r1-s2 (including) | 19.4-r1-s2 (including) |
| Junos | Juniper | 19.4-r1-s3 (including) | 19.4-r1-s3 (including) |
| Junos | Juniper | 19.4-r1-s4 (including) | 19.4-r1-s4 (including) |
| Junos | Juniper | 19.4-r2 (including) | 19.4-r2 (including) |
| Junos | Juniper | 19.4-r2-s1 (including) | 19.4-r2-s1 (including) |
| Junos | Juniper | 19.4-r2-s2 (including) | 19.4-r2-s2 (including) |
| Junos | Juniper | 19.4-r2-s3 (including) | 19.4-r2-s3 (including) |
| Junos | Juniper | 19.4-r2-s4 (including) | 19.4-r2-s4 (including) |
| Junos | Juniper | 19.4-r2-s5 (including) | 19.4-r2-s5 (including) |
| Junos | Juniper | 19.4-r3-s6 (including) | 19.4-r3-s6 (including) |
| Junos | Juniper | 20.1 (including) | 20.1 (including) |
| Junos | Juniper | 20.1-r1 (including) | 20.1-r1 (including) |
| Junos | Juniper | 20.2 (including) | 20.2 (including) |
| Junos | Juniper | 20.2-r1 (including) | 20.2-r1 (including) |
| Junos | Juniper | 20.2-r1-s1 (including) | 20.2-r1-s1 (including) |
| Junos | Juniper | 20.2-r1-s2 (including) | 20.2-r1-s2 (including) |
| Junos | Juniper | 20.2-r1-s3 (including) | 20.2-r1-s3 (including) |
| Junos | Juniper | 20.2-r2 (including) | 20.2-r2 (including) |
| Junos | Juniper | 20.2-r2-s1 (including) | 20.2-r2-s1 (including) |
| Junos | Juniper | 20.2-r2-s2 (including) | 20.2-r2-s2 (including) |
| Junos | Juniper | 20.2-r2-s3 (including) | 20.2-r2-s3 (including) |
| Junos | Juniper | 20.2-r3 (including) | 20.2-r3 (including) |
| Junos | Juniper | 20.2-r3-s1 (including) | 20.2-r3-s1 (including) |
| Junos | Juniper | 20.2-r3-s2 (including) | 20.2-r3-s2 (including) |
| Junos | Juniper | 20.3 (including) | 20.3 (including) |
| Junos | Juniper | 20.3-r1 (including) | 20.3-r1 (including) |
| Junos | Juniper | 20.3-r1-s1 (including) | 20.3-r1-s1 (including) |
| Junos | Juniper | 20.3-r1-s2 (including) | 20.3-r1-s2 (including) |
| Junos | Juniper | 20.3-r2 (including) | 20.3-r2 (including) |
| Junos | Juniper | 20.3-r2-s1 (including) | 20.3-r2-s1 (including) |
| Junos | Juniper | 20.3-r3 (including) | 20.3-r3 (including) |
| Junos | Juniper | 20.3-r3-s1 (including) | 20.3-r3-s1 (including) |
| 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 | 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 | 21.2 (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-r3 (including) | 21.2-r3 (including) |
The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:
In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.