CVE-2021-0294
Junos OS: QFX5000 Series and EX4600 Series: Enhanced storm control might not work leading to partial Denial of Service
- Published
- Updated
- Reserved
- Assigned by
- juniper
Description
A vulnerability in Juniper Networks Junos OS, which only affects the release 18.4R2-S5, where a function is inconsistently implemented on Juniper Networks Junos QFX5000 Series and EX4600 Series, and if "storm-control enhanced" is configured, can lead to the enhanced storm control filter group not be installed. It will cause storm control not to work hence allowing an attacker to cause high CPU usage or packet loss issues by sending a large amount of broadcast or unknown unicast packets arriving the device. This issue affects Juniper Networks QFX5100, QFX5110, QFX5120, QFX5200, QFX5210, EX4600, and EX4650, and QFX5100 with QFX 5e Series image installed. QFX5130 and QFX5220 are not affected from this issue. This issue affects Juniper Networks Junos OS 18.4R2-S5 on QFX5000 Series and EX4600 Series. No other product or platform is affected by this vulnerability.
Timeline
ID reserved
By juniper
- 9 months later
· 9 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
- EPSS (exploitation in 30 days)
- 0.95% · top 39% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
Affected products
- affected 18.4R2-S5
What to do
Solution: The following software releases has been updated to resolve this specific issue: Junos OS 18.4R2-S6.
Workaround: There are no viable workarounds for this issue.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References (1)
- https://kb.juniper.net/JSA11196 (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-0294)Record last updated .