CVSS 4.0
7.7 highCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:L/SA:NCVE-2026-121287 Security Advisory 0221
High (7.7) in arista networks eos. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
An unauthenticated attacker on an adjacent network segment can send crafted RIPv2 packets to a RIP-enabled interface on the device to trigger the Rip agent crash without providing valid credentials. Repeated exploitation reliably interrupts routing service on the affected device, which may also disrupt routing for other devices that depend on it. In a worst-case scenario, the vulnerability may allow an attacker to execute arbitrary code on the affected device.
Severity
CVSS 3.1
8.8 highCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 15th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: total, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-124 Buffer Underwrite (Buffer Underrun)
- Published
- Modified
- Assigned by
- Arista (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
Ask an AI about this CVE
Show the prompt
Explain CVE-2026-121287 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-121287?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-121287?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-121287 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Badge for a README or a site
An image that stays current: it is drawn from the data each time it is fetched (a host that proxies images, as GitHub does, may show its copy for a while). Markdown:
[](https://cve.bz/cve/CVE-2026-121287)
HTML:
<a href="https://cve.bz/cve/CVE-2026-121287"><img src="https://cve.bz/cve/badge/CVE-2026-121287.svg" alt="CVE-2026-121287"></a>
Affected
- arista networks:eos
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| Arista Networks EOS | 4.37.0F |
| Arista Networks EOS | from 4.36.0F through 4.36.2F |
| Arista Networks EOS | from 4.35.0F through 4.35.6M |
| Arista Networks EOS | from 4.34.0F through 4.34.8M |
| Arista Networks EOS | from 4.33.0F through 4.33.10M |
| Arista Networks EOS | from 4.32.0F before 4.33.0F |
| Arista Networks EOS | from 1.0.0 before 4.32.0F |