Improper access control in Arista EOS
Priority LOW 35CWE-284Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-284.
Summary
On affected Arista EOS platforms, if a VXLAN match rule exists in an IPv4 access-list that is applied to the ingress of an L2 or an L3 port/SVI, the VXLAN rule and subsequent ACL rules in that access list will ignore the specified IP protocol.
Why it matters now
EPSS 0.00882 59th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Arista | EOS | 4.26.3M – 4.26.0; 4.27.0F – 4.27.0 | — | No fix listed | CNA |
- EOS VendorArista Affected 4.26.3M – 4.26.0; 4.27.0F – 4.27.0 Fixed in — No fix listed CNA
CPE configurations NVD · 18
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* | 4.26 to before 4.26.4m; 4.27 to before 4.27.1f | Vulnerable | Arista |
| cpe:2.3:h:arista:ccs-710p-12:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-710p-16p:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-720xp-24y6:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-720xp-24zy4:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-720xp-48y6:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-720xp-48zc2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-720xp-96zc2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-722xpm-48y4:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:ccs-722xpm-48zy8:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
- cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* Versions 4.26 to before 4.26.4m; 4.27 to before 4.27.1f Vulnerable ·Arista
- cpe:2.3:h:arista:ccs-710p-12:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-710p-16p:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-720xp-24y6:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-720xp-24zy4:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-720xp-48y6:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-720xp-48zc2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-720xp-96zc2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-722xpm-48y4:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:ccs-722xpm-48zy8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
Show 8 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:h:arista:dcs-7010tx-48:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050cx3-32s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050cx3m-32s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050sx3-48c8:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050sx3-48yc12:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050sx3-48yc8:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050sx3-96yc8:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
| cpe:2.3:h:arista:dcs-7050tx3-48c8:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Arista |
- cpe:2.3:h:arista:dcs-7010tx-48:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050cx3-32s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050cx3m-32s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050sx3-48c8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050sx3-48yc12:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050sx3-48yc8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050sx3-96yc8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
- cpe:2.3:h:arista:dcs-7050tx3-48c8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-28505
- 2026-10-03 Alias added: GHSA-3p5w-c6fg-w249
References
More Arista Eos vulnerabilities
- TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
- TI-2026-06569 Arista EOS Unexpected Tunnel Protocol Decapsulation and Forwarding Bypass KEVCVSS 4.0MEDIUM 6.9
- TI-2017-10594 Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a… CVSS 3.1CRITICAL 9.8
- TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
- TI-2020-08209 utility.c in telnetd in netkit telnet through 0.17 allows remote attackers to execute… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2021-28505 · CVE Program
- CVE-2021-28505 · NVD
- FIRST EPSS
- GHSA-3p5w-c6fg-w249 · GitHub Advisory Database · CC BY 4.0
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