VulnerabilityPublished 7 May 2026Updated 11 May 2026

CVE-2026-42880: V3 · ArgoCD ServerSideDiff is vulnerable to Kubernetes Secret Extraction

Affects github.com/argoproj/argo-cd/v3Source GCVE Database

Authoritative record:CVE-2026-42880· Critical 9.6

Not known to be exploited · CVSS 9.6 Critical : upgrade to 3.2.11 as a priority.

Data as of 27 Oct 2026, 01:11 UTC

CVSS 3.1 base score

9.6Critical

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

Patch: Available – fixed in 3.2.11, 3.3.9

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 github.com/argoproj/argo-cd/v3 to 3.2.11; github.com/argoproj/argo-cd/v3 to 3.3.9.

Affected software

Product	Affected	Fixed in
Gogithub.com/argoproj/argo-cd/v3	Affected >=3.2.0 <3.2.11	Fixed in 3.2.11
Gogithub.com/argoproj/argo-cd/v3	Affected >=3.3.0 <3.3.9	Fixed in 3.3.9

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and should be applied immediately. Fixed versions are 3.2.11 and 3.3.9. Upgrade to these or later versions to remediate the vulnerability. There is no indication that the vulnerability is mitigated by configuration changes alone. Follow the vendor's official advisory for patching instructions.

Description

CVE-2026-42880 is a critical vulnerability in Argo CD's ServerSideDiff endpoint that allows attackers with read-only access to extract plaintext Kubernetes Secret data. The issue arises because the ServerSideDiff endpoint returns unmasked secret data from the Kubernetes API server's Server-Side Apply dry-run response when a specific annotation is set, bypassing the usual masking defenses. This can expose sensitive secret information stored in etcd. The vulnerability affects Argo CD versions 3.2.0 through 3.2.10 and 3.3.0 through 3.3.8 and is fixed in versions 3.2.11 and 3.3.9.

Impact

An attacker with read-only access to Argo CD can extract plaintext Kubernetes Secret data from etcd, potentially exposing sensitive credentials or configuration secrets. This compromises confidentiality and could lead to further attacks or data breaches. The vulnerability does not affect availability or integrity directly but has a high confidentiality impact.

Summary

Argo CD masks Kubernetes Secret data in most endpoints but fails to do so in the ServerSideDiff gRPC/REST endpoint when the application annotation argocd.argoproj.io/compare-options: IncludeMutationWebhook=true is set. This causes the endpoint to return raw, unmasked secret data from the Kubernetes Server-Side Apply dry-run response, which includes real secret values read from etcd. The vulnerability requires only read access via RBAC, which all authenticated Argo CD users have by default. The issue is due to skipping the removeWebhookMutation() defense that normally strips non-Argo CD-managed fields. The vulnerability is present in versions >=3.2.0 <3.2.11 and >=3.3.0 <3.3.9 and has a CVSS 3.1 score of 9.6 (critical). A proof-of-concept exploit demonstrates how to extract secret data via this endpoint.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-212Improper Removal of Sensitive Information Before Storage or Transfer (opens in a new tab)
Base weakness
The product stores, transfers, or shares a resource that contains sensitive information, but it does not properly remove that information before the product makes the resource available to unauthorized actors.
Requirements
Clearly specify which information should be regarded as private or sensitive, and require that the product offers functionality that allows the user to cleanse the sensitive information from the resource before it is published or exported to other parties.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Implementation · Operation · Attack Surface Reduction
Some tools can automatically analyze documents to redact, strip, or "sanitize" private information, although some human review might be necessary. Tools may vary in terms of which document formats can be processed.
OWASP ASVS 4.0.3
V8.3.2 (opens in a new tab)
Attack patterns
Windows ::DATA Alternate Data Stream (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 01:11 UTC

WeaknessesCWE-200, CWE-212

Technical details

References

Community reviews

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