Arista EOS up to 4.33.9M/4.34.7.1M/4.35.5M DHCP Relay Service input validation

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
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CTI Interest Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in Arista EOS up to 4.33.9M/4.34.7.1M/4.35.5M. This affects an unknown part of the component DHCP Relay Service. Such manipulation leads to input validation. This vulnerability is referenced as CVE-2026-19655. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Arista EOS up to 4.33.9M/4.34.7.1M/4.35.5M and classified as critical. Affected by this issue is an unknown code block of the component DHCP Relay Service. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is availability. CVE summarizes:

On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthenticated attacker connected to a client-facing VLAN(s) where the relay is configured can send a specially crafted packet that causes the DHCP Relay service to restart.

The advisory is shared for download at arista.com. This vulnerability is handled as CVE-2026-19655 since 08/12/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/15/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.5
VulDB Temp Score: 7.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (Arista): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/12/2026 CVE reserved
09/15/2026 +34 days Advisory disclosed
09/15/2026 +0 days VulDB entry created
09/15/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: arista.com
Status: Confirmed

CVE: CVE-2026-19655 (🔒)
GCVE (CVE): GCVE-0-2026-19655
GCVE (VulDB): GCVE-100-404780

Entryinfo

Created: 09/15/2026 23:15
Changes: 09/15/2026 23:15 (39), 09/15/2026 23:16 (34)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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