CVE-2026-73458: Arista Networks EOS · Incorrect Implementation of Authentication Algorithm
Affects Arista Networks EOSSource CVE Database V5
Not known to be exploited · CVSS 8.2 High · fixed in 4.36.2F : patch Arista Networks EOS soon.
Data as of 30 Oct 2026, 20:25 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.36.2F, 4.35.6M, 4.34.8M +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade EOS and arista/eos to 4.36.2F, 4.35.6M, 4.34.8M or 4.33.9M.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
|
Aristaarista/eospkg:rpm/arista/eosOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, consider disabling authenticated BFD sessions if feasible or monitoring BFD session stability. Follow Arista Networks' official advisories for updates and fixes.
Description
On affected platforms running Arista EOS with authenticated Bidirectional Forwarding Detection (BFD) sessions configured, a specially crafted packet can cause the BFD session(s) to go down. This may result in undesirable network changes because various routing protocols monitor status on BFD session(s).