CVE-2026-57029
Junos OS Evolved: QFX Series: When sFlow collector reachability changes evo-pfemand process can crash
A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS).
When the reachability of an sFlow collector changes, the corresponding next-hop entry is updated. If this update occurs simultaneously with the sFlow thread accessing the next-hop data (which is outside the attackers control), it causes the evo-pfemand process to crash, impacting all traffic forwarding until the automatic process restart has completed.
This issue affects Junos OS Evolved on QFX Series:
- all 23.2 versions,
- 23.4 versions before 23.4R2-S7-EVO,
- 24.2 versions before 24.2R2-S5-EVO,
- 24.4 versions before 24.4R2-S3-EVO,
- 25.2 versions before 25.2R2-EVO.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Junos OS Evolved: QFX Series: When sFlow collector reachability changes evo-pfemand process can crash
A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS).
When the reachability of an sFlow collector changes, the corresponding next-hop entry is updated. If this update occurs simultaneously with the sFlow thread accessing the next-hop data (which is outside the attackers control), it causes the evo-pfemand process to crash, impacting all traffic forwarding until the automatic process restart has completed.
This issue affects Junos OS Evolved on QFX Series:
- all 23.2 versions,
- 23.4 versions before 23.4R2-S7-EVO,
- 24.2 versions before 24.2R2-S5-EVO,
- 24.4 versions before 24.4R2-S3-EVO,
- 25.2 versions before 25.2R2-EVO.
- Record
CVE-2026-57029- CVSS 4.0
- 6.0 Medium
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-820
- Updated
- 2026-11-02
EUVDEUVD-2026-42718
A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS).
When the reachability of an sFlow collector changes, the corresponding next-hop entry is updated. If this update occurs simultaneously with the sFlow thread accessing the next-hop data (which is outside the attackers control), it causes the evo-pfemand process to crash, impacting all traffic forwarding until the automatic process restart has completed.
This issue affects Junos OS Evolved on QFX Series:
- all 23.2 versions,
- 23.4 versions before 23.4R2-S7-EVO,
- 24.2 versions before 24.2R2-S5-EVO,
- 24.4 versions before 24.4R2-S3-EVO,
- 25.2 versions before 25.2R2-EVO.
- Record
EUVD-2026-42718- CVSS 4.0
- 6.0 Medium
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-x7gh-cpmx-x9cj
A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos...
A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS).
When the reachability of an sFlow collector changes, the corresponding next-hop entry is updated. If this update occurs simultaneously with the sFlow thread accessing the next-hop data (which is outside the attackers control), it causes the evo-pfemand process to crash, impacting all traffic forwarding until the automatic process restart has completed.
This issue affects Junos OS Evolved on QFX Series:
- all 23.2 versions,
- 23.4 versions before 23.4R2-S7-EVO,
- 24.2 versions before 24.2R2-S5-EVO,
- 24.4 versions before 24.4R2-S3-EVO,
- 25.2 versions before 25.2R2-EVO.
- Record
GHSA-x7gh-cpmx-x9cj- CVSS 4.0
- 6.0 Medium
CVSS:4.0/AV:A/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:X/V:X/RE:M/U:X - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-820
- Updated
- 2026-11-02
NVD
A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS).
When the reachability of an sFlow collector changes, the corresponding next-hop entry is updated. If this update occurs simultaneously with the sFlow thread accessing the next-hop data (which is outside the attackers control), it causes the evo-pfemand process to crash, impacting all traffic forwarding until the automatic process restart has completed.
This issue affects Junos OS Evolved on QFX Series:
- all 23.2 versions,
- 23.4 versions before 23.4R2-S7-EVO,
- 24.2 versions before 24.2R2-S5-EVO,
- 24.4 versions before 24.4R2-S3-EVO,
- 25.2 versions before 25.2R2-EVO.
- Record
CVE-2026-57029- CVSS 4.0
- 6.0 Medium
CVSS:4.0/AV:A/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:X/V:X/RE:M/U:X - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-820
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-57029 is a medium vulnerability (CVSS 6.0) in Juniper Junos Os Evolved, published July 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 8th percentile. No source names a fixed version.