CVE-2021-28504On Arista Strata family products which have “TCAM profile” feature enabled when Port IPv4 access-list has a rule which matches on “vxlan” as protocol then that rule and subsequent rules ( rules declared after it in ACL ) do not match on IP protocol fi ...
- 7.5HighCVSS base score
- 0.73%Exploitation in 30 daysEPSS · top 45% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
On Arista Strata family products which have “TCAM profile” feature enabled when Port IPv4 access-list has a rule which matches on “vxlan” as protocol then that rule and subsequent rules ( rules declared after it in ACL ) do not match on IP protocol field as expected.
Timeline
ID reserved
By Arista
- 13 months later
· 13 months later
Published
- 2 years later
· 2 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 |
|---|---|---|---|
| AristaCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.73% · top 45% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- affected 4.26.3F – ≤ 4.26.0
- affected 4.27.0F – ≤ 4.27.0
What to do
Solution: The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Artista recommends customers move to the latest version of each release that contains all the fixes listed below. CVE-2021-28504 has been fixed in the following releases: 4.26.4F and later releases in the 4.26.x train 4.27.1M and later releases in the 4.27.x train
Workaround: Replace "vxlan" IP protocol match with match on IP protocol "udp" and Layer 4 destination port for VxLAN encapsulated packets i.e 4789. If VXLAN L4 destination port number is not the default 4789 then use the configured L4 destination port number.
References
References1
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)
- EUVD EUVD-2021-15180 (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://cveledger.app/cve/CVE-2021-28504)Record last updated .