CVE-2026-21905 is a high severity vulnerability with a CVSS score of 7.5. No known exploits currently, and patches are available.
Very low probability of exploitation
EPSS predicts the probability of exploitation in the next 30 days based on real-world threat data, complementing CVSS severity scores with actual risk assessment.
A Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).
On SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.
This issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.
This issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:
| Vendor | Product |
|---|---|
| Juniper | Junos |
| Juniper | Mx960 |
| Juniper | Mx480 |
| Juniper | Mx2010 |
| Juniper | Srx2300 |
| Juniper | Srx300 |
| Juniper | Srx4120 |
| Juniper | Mx10008 |
| Juniper | Srx320 |
| Juniper | Mx2008 |
And 18 more...
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