GHSA-fmxq-cgp8-87wp BIT-argo-cd-2026-77459 CVE-2026-77459 GO-2026-6784
Argo CD: AppProject destination-namespace and resource restrictions bypassed by PreDelete/PostDelete resource hooks
- Severity
- 9.9 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 0.50%
- Chance of exploitation in the next 30 days. Higher than 42.68% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-863 Incorrect Authorization
- Fix
3.3.15- Upgrade github.com/argoproj/argo-cd/v3 to this version or later
Description
Impact
Argo CD checks an Application's AppProject before it creates resources during a sync. That check covers destination namespaces and servers, cluster-scoped resource allow and deny lists, and namespaced resource allow and deny lists, including resource names. PreDelete and PostDelete hooks skip it. When the Application is deleted, Argo CD creates those hooks with the application-controller's credentials on the destination cluster.
All versions from v2.10.0 onward are affected, including every currently supported release. v2.9.22 and earlier are not. PostDelete hooks were introduced in dcc17f70bf (2023-12-18, #16595) and first released in v2.10.0. That creation path has never applied the project check. PreDelete hooks, added in 3bf3d8a212 (2025-12-05, #22288) and first released in v3.3.0, use the same path. v3.2.12 and earlier do not have PreDelete hooks. PreSync, Sync, PostSync, and SyncFail hooks still go through the project check.
A user who can push to the Git repository an Application syncs from can commit a hook whose namespace, group, kind, or name the AppProject would refuse on sync. The controller adds the delete finalizer when it sees the hook, and the Application stays Synced until someone deletes it. Deleting the Application creates the hook. What that can reach is bounded by the application-controller's access to the destination cluster. In a typical install that access is broad, so a tenant can create a cluster-scoped object such as a ClusterRoleBinding, or an object in a namespace the project does not allow. A hook with no deletion policy is removed after it succeeds. A deletion policy that does not remove the hook on success leaves the object in the cluster. A hook such as a Job can create further objects that Argo CD does not clean up.
Patches
A patch for this vulnerability has been released in the following Argo CD versions:
- v3.6.0-rc2
- v3.5.4
- v3.4.10
- v3.3.15
The fix applies the same AppProject destination and resource checks used on sync before creating a PreDelete or PostDelete hook.
Argo CD 2.x and 3.0 through 3.2 are out of support and will not receive a patch. Upgrade to a patched 3.3 or newer release.
Workarounds
There is no configuration setting that applies the project check to delete hooks while those hooks stay in use.
- Do not grant untrusted users write access to Git repositories that back Applications in restrictive AppProjects.
- Limit who can delete Applications. Deletion is what runs PreDelete and PostDelete hooks.
- Tighten the application-controller's Kubernetes access so a hook cannot reach sensitive namespaces or APIs.
Credits
The Argo CD team would like to thank @RealFakeAccount, @AdamKorcz, @0xshylines, @thevilledev, @HenriWilliams, @cherez0ff, @ARSB1, and @zwindler for responsibly disclosing this issue according to our security reporting guidelines.
References
- PostDelete introducing commit: dcc17f70bf7db973fe480b8b613189b2c5ac4b4b (#16595), first released in v2.10.0
- PreDelete introducing commit: 3bf3d8a2124e772ac651f3fd42375c4e9b8008af (#22288), first released in v3.3.0
- AppProject specification
- Resource hooks
For more information
- Open an issue in the Argo CD issue tracker or discussions
- Join us on Slack in channel #argo-cd
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/argoproj/argo-cd | all versions |
No fix yet |
| github.com/argoproj/argo-cd/v2 | >= 2.10.0, <= 2.14.21 |
No fix yet |
| github.com/argoproj/argo-cd/v2 | >= 2.10.0 |
No fix yet |
| github.com/argoproj/argo-cd/v3 | >= 3.0.0, < 3.3.15 |
3.3.15 |
| github.com/argoproj/argo-cd/v3 | >= 3.4.0, < 3.4.10 |
3.4.10 |
| github.com/argoproj/argo-cd/v3 | >= 3.5.0, < 3.5.4 |
3.5.4 |
| github.com/argoproj/argo-cd/v3 | >= 3.6.0-rc1, < 3.6.0-rc2 |
3.6.0-rc2 |
| github.com/argoproj/argo-cd/v3 | >= 3.0.0, < 3.3.15>= 3.4.0, < 3.4.10>= 3.5.0, < 3.5.4>= 3.6.0-rc1, < 3.6.0-rc2 |
3.3.153.4.103.5.43.6.0-rc2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/argoproj/argo-cd/v3 Go → 3.3.15
- go
go get github.com/argoproj/argo-cd/v3@v3.3.15 && go mod tidy
Severity breakdown
CVSS 3.1 9.9
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-863: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Packages
Other links
- github.com/argoproj/argo-cd/security/advisories/GHSA-fmxq-cgp8-87wp
- github.com/argoproj/argo-cd/commit/1149cdc6e932208c4402183cc3d7b7485239940c
- github.com/argoproj/argo-cd/commit/4bc8085b0a6d2296b849539d3d09fc7be7a4a511
- github.com/argoproj/argo-cd/commit/7f0a05834b05103d69d7c150e1ee36541b314696
- github.com/argoproj/argo-cd/commit/d5dd7019ee65be8895133fe4df554e28074242c4
- github.com/argoproj/argo-cd/releases/tag/v3.3.15
- github.com/argoproj/argo-cd/releases/tag/v3.4.10
- github.com/argoproj/argo-cd/releases/tag/v3.5.4
- github.com/argoproj/argo-cd/releases/tag/v3.6.0-rc2
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-j6cw-g6p4-7hch Argo CD repo-server command injection via crafted SSH repository SOCKS5 proxy URL | High | Also affects github.com/argoproj/argo-cd |
| GHSA-h98r-wv3h-fr38 Argo CD: Stored XSS in application link annotations enables developer-to-admin privilege escalation | High | Also affects github.com/argoproj/argo-cd |
| GO-2026-5618 Argo CD: Kubernetes Secret Extraction via ArgoCD ServerSideDiff via sensitive annotations | Medium | Also affects github.com/argoproj/argo-cd |
| GO-2026-5099 ArgoCD ServerSideDiff is vulnerable to Kubernetes Secret Extraction | Critical | Also affects github.com/argoproj/argo-cd |
| GHSA-gpx4-37g2-c8pv Argo CD Unauthenticated Remote DoS via malformed Azure DevOps git.push webhook | High | Also affects github.com/argoproj/argo-cd |
| GHSA-wp4p-9pxh-cgx2 argo-cd vulnerable unauthenticated DoS via malformed Gogs webhook payload | High | Also affects github.com/argoproj/argo-cd |
| GHSA-f9gq-prrc-hrhc Unauthenticated argocd-server panic via a malicious Bitbucket-Server webhook payload | High | Also affects github.com/argoproj/argo-cd |
| GHSA-g88p-r42r-ppp9 Repository Credentials Race Condition Crashes Argo CD Server | Medium | Also affects github.com/argoproj/argo-cd |
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