VulnerabilityPublished 10 Nov 2026

CVE-2026-120974: Arista Networks EOS · Authentication Bypass by Capture-replay

Affects Arista Networks EOSSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium · fixed in 4.33.0F : update Arista Networks EOS when convenient.

Data as of 10 Nov 2026, 20:34 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (Arista)	CVSS 3.1	5.3
CNA (Arista)	CVSS 4.0	6.9

Patch: Available – fixed in 4.33.0F, 4.32.0F, 4.31.0F +2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 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 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Arista NetworksEOS	Affected >=4.27.0F <4.28.0F >=4.28.0F <=4.28.13M >=4.29.0F <4.30.0F >=4.30.0F <4.31.0F >=4.31.0F <4.32.0F >=4.32.0F <4.33.0F >=4.33.0F <=4.33.8M >=4.34.0F <=4.34.7M >=4.35.0F <=4.35.5M >=4.36.0F <=4.36.1F	Fixed in 4.33.0F 4.32.0F 4.31.0F 4.30.0F 4.28.0F

AI-suggested

Fixed versions are available starting from 4.28.0F, 4.30.0F, 4.31.0F, 4.32.0F, and 4.33.0F. Operators should upgrade affected EOS versions to these fixed releases to ensure proper enforcement of IPsec anti-replay protection. No other mitigations or workarounds are indicated.

Description

CVE-2026-120974 is an authentication bypass vulnerability in Arista Networks EOS affecting the IPsec AutoVPN feature with dynamic paths. The IPsec replay window may not be enforced as configured, causing the anti-replay protection to be silently inactive. This does not allow decryption of IPsec traffic but may permit replay of previously valid protected traffic. The issue affects multiple versions of EOS prior to fixed releases. The vulnerability has a medium severity rating with a CVSS score of 5.3.

CWE-294Authentication Bypass by Capture-replay (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
Architecture and Design
Utilize some sequence or time stamping functionality along with a checksum which takes this into account in order to ensure that messages can be parsed only once.
Architecture and Design
Since any attacker who can listen to traffic can see sequence numbers, it is necessary to sign messages with some kind of cryptography to ensure that sequence numbers are not simply doctored along with content.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Session Sidejacking (opens in a new tab)
Kerberoasting (opens in a new tab)
Remote Services with Stolen Credentials (opens in a new tab)
Windows Admin Shares with Stolen Credentials (opens in a new tab)
Reusing Session IDs (aka Session Replay) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

arista.com/en/support/advisories-notices/security-advisory/25041-security-advisory-0219 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2026, 20:33 UTC

WeaknessesCWE-294

Technical details

References

Community reviews

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