CVE-2026-57030
MEDIUMA Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX…
Description
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;
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-57030 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-57030 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-57030. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-57030 in your dependencies?
O3 detects CVE-2026-57030 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.