CVE-2026-57030
published 2026-07-09CVE-2026-57030: A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper…
PriorityP434medium5.9CVSS 3.1
AVNACHPRNUINSUCNINAH
EPSS
0.38%
30.4th percentile
A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
As part of the stateful traffic processing on SRX Series devices flows are being established, and removed when not needed anymore. During the removal process the timeout of a flow should be set to 3 seconds and consequentially the flow should be removed shortly after. Due to a race condition occurring when setting the timeout there is a chance (the exact conditions are outside the attackers control) that the timeout is instead set to a very high value of larger than 10,000 seconds:
user@host> show security flow session | match timeout
Session ID: 98784248524, Policy name: PROD-FLOW/4, HA State: Active, Timeout: 85250, Session State: Valid
This will lead to an accumulation of flows which can be observed by an ever-increasing value of invalidated sessions in the output of 'show security flow session summary':
user@host> show security flow session summary | match invalid
Invalidated sessions: 216931These sessions can't be cleared manually with the 'clear security flow session' command, which will either lead to forwarding to stop (and the system needs to be manually recovered with a reboot) or to a flowd core and automatic reboot.
This issue affects Junos OS on SRX Series:
* 24.2 versions before 24.2R2-S3,
* 24.4 versions before 24.4R2-S1, 24.4R2-S2,
* 25.2 versions before 25.2R1-S2, 25.2R2.
This issue does not affect releases earlier than 24.2R1;
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper_networks | junos_os | >= 24.2 < 24.2R2-S3 | 24.2R2-S3 |
| juniper_networks | junos_os | >= 24.4 < 24.4R2-S1 | 24.4R2-S1 |
| juniper_networks | junos_os | >= 25.2 < 25.2R1-S2 | 25.2R1-S2 |
CVSS provenance
nvdv3.15.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv4.08.2HIGHCVSS: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:Y/R:U/V:X/RE:M/U:X
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VulDB
Juniper Junos OS up to 24.2R0/24.2R2-S2/24.4R2-S0/25.2R1-S1 Packet Forwarding Engine flowd setting timeout race condition
vuldb·2026-07-10·CVSS 5.9
CVE-2026-57030 [MEDIUM] Juniper Junos OS up to 24.2R0/24.2R2-S2/24.4R2-S0/25.2R1-S1 Packet Forwarding Engine flowd setting timeout race condition
A vulnerability was found in Juniper Junos OS up to 24.2R0/24.2R2-S2/24.4R2-S0/25.2R1-S1. It has been declared as critical. This issue affects the function Setting of the file flowd of the component Packet Forwarding Engine. Such manipulation of the argument timeout leads to race condition.
This vulnerability is listed as CVE-2026-57030. The attack may be performed from remote. There is no available exploit.
GHSA
A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an u
ghsa_unreviewed·2026-07-10
CVE-2026-57030 [HIGH] CWE-362 A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an u
A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
As part of the stateful traffic processing on SRX Series devices flows are being established, and removed when not needed anymore. During the removal process the timeout of a flow should be set to 3 seconds and consequentially the flow should be removed shortly after. Due to a race condition occurring when setting the timeout there is a chance (the exact conditions are outside the attackers control) that the timeout is instead set to a very high value of larger than 10,000 seconds:
user@host> show security flow sessi
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-07-09
Published