Coder's privilege escalation vulnerability could lead to a cross workspace compromise

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No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Coder allows organizations to provision remote development environments via Terraform. In versions 2.22.0 through 2.24.3, 2.25.0 and 2.25.1, Coder can be compromised through insecure session handling in prebuilt workspaces. Coder automatically generates a session token for a user when a workspace is started. It is automatically exposed via coder_workspace_owner.session_token. Prebuilt workspaces are initially owned by a built-in prebuilds system user. When a prebuilt workspace is claimed, a new session token is generated for the user that claimed the workspace, but the previous session token for the prebuilds user was not expired. Any Coder workspace templates that persist this automatically generated session token are potentially impacted. This is fixed in versions 2.24.4 and 2.25.2.

Source published

6 Sep 2025 02:30:08 UTC

Source modified

8 Sep 2025 16:45:15 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Coder allows organizations to provision remote development environments via Terraform. In versions 2.22.0 through 2.24.3, 2.25.0 and 2.25.1, Coder can be compromised through insecure session handling in prebuilt workspaces. Coder automatically generates a session token for a user when a workspace is started. It is automatically exposed via coder_workspace_owner.session_token. Prebuilt workspaces are initially owned by a built-in prebuilds system user. When a prebuilt workspace is claimed, a new session token is generated for the user that claimed the workspace, but the previous session token for the prebuilds user was not expired. Any Coder workspace templates that persist this automatically generated session token are potentially impacted. This is fixed in versions 2.24.4 and 2.25.2.

Source published

Sep 6, 2025, 2:30:08 AM (timezone not stated)

Source modified

Sep 8, 2025, 4:45:15 PM (timezone not stated)

Observed here

7 Nov 2026 02:42:45 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Coder allows organizations to provision remote development environments via Terraform. In versions 2.22.0 through 2.24.3, 2.25.0 and 2.25.1, Coder can be compromised through insecure session handling in prebuilt workspaces. Coder automatically generates a session token for a user when a workspace is started. It is automatically exposed via coder_workspace_owner.session_token. Prebuilt workspaces are initially owned by a built-in prebuilds system user. When a prebuilt workspace is claimed, a new session token is generated for the user that claimed the workspace, but the previous session token for the prebuilds user was not expired. Any Coder workspace templates that persist this automatically generated session token are potentially impacted. This is fixed in versions 2.24.4 and 2.25.2.

Source published

6 Sep 2025 03:15:40 UTC

Source modified

19 Oct 2026 17:10:00 UTC

Observed here

25 Oct 2026 03:17:18 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS 3.1 · [email protected] · Primary · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

## Summary Insecure session handling opened room for a privilege escalation scenario in which [prebuilt workspaces](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces) could be compromised by abusing a shared system identity. ## Details Coder automatically generates a session token for a user when a workspace is started. It is automatically exposed via [`coder_workspace_owner.session_token`](https://registry.terraform.io/providers/coder/coder/latest/docs/data-sources/workspace_owner#session_token-1). Prebuilt workspaces are initially owned by a built-in `prebuilds` system user. When a prebuilt workspace is claimed, a new session token is generated for the user that claimed the workspace, but the previous session token for the `prebuilds` user was not expired. Any Coder workspace templates that persist this automatically generated session token are potentially impacted. For example, the [coder-login module](https://github.com/coder/registry/blob/8677e7d52b374b025c4820d09049dc6b008beee8/registry/coder/modules/coder-login/run.sh) allows template authors to automatically configure the coder CLI to be authenticated with the Coder deployment. This causes a script to be run on workspace startup that runs the command `coder login` using the automatically generated user session token c.f. [https://github.com/coder/registry/blob/8677e7d52b374b025c4820d09049dc6b008beee8/registry/coder/modules/coder-login/main.tf#L23](https://github.com/coder/registry/blob/8677e7d52b374b025c4820d09049dc6b008beee8/registry/coder/modules/coder-login/main.tf#L23) This module was originally written before the inception of the [prebuilds](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces) feature in Coder, which essentially creates a "pre-warmed" pool of workspaces owned by a particular `prebuilds` system user. When this module is invoked on a prebuilt workspace, it causes the Coder CLI inside the workspace to persist the session token for the `prebuilds` user to disk. Because the `coder-login` module checks if the CLI is authenticated, the script exits early before updating the session token, leaving the Coder CLI authenticated as the `prebuilds`user upon claim: ## Impact > Important: **Deployments that have never utilized the [prebuilds](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces) feature are not affected by this vulnerability.** This vulnerability requires a previously authenticated user to claim a prebuilt workspace from a template configured to store the prebuilds user session token as described above. The `prebuilds` user has no specific roles, so its credential has the same level of access as a regular member user, meaning a user with the `prebuilds` user's credential can move laterally to any other prebuilt workspace, or create new workspaces as the `prebuilds` user. This means that a malicious authenticated actor can potentially execute code on other workspaces owned by the `prebuilds` user and potentially access information of other users once they claim a previously poisoned workspace. ## Remediation Fixed in https://github.com/coder/coder/pull/19667 Note that prebuilt workspaces claimed previous to the fix may have been affected by this vulnerability. It is recommended that users re-create their workspace if it was created from a prebuild. To identify potentially affected workspaces, run the following SQL query against the Coder database: ```sql SELECT w.id, w.name, w.owner_id, u.email FROM workspaces w LEFT JOIN users u ON u.id = w.owner_id WHERE w.owner_id <> 'c42fdf75-3097-471c-8c33-fb52454d81c0'::uuid AND NOT w.deleted AND EXISTS ( SELECT 1 FROM workspace_builds AS wb WHERE wb.workspace_id = w.id AND wb.initiator_id = 'c42fdf75-3097-471c-8c33-fb52454d81c0'::uuid ); ``` > Previous manually created tokens for the prebuilds user are left as-is. You may wish to review these via `coder tokens list --all` --- [Premium license](https://coder.com/docs/admin/licensing) customers can also take advantage of the [audit logs](https://coder.com/docs/admin/security/audit-logs) feature to query actions performed by the `prebuilds` user. Following [filter](https://coder.com/docs/admin/security/audit-logs#how-to-filter-audit-logs) can be used to verify if no [API keys](https://coder.com/docs/reference/api/users#create-token-api-key) were created by the `prebuilds` user > would indicate a potentially malicious action aimed at achieving [persistence](https://attack.mitre.org/tactics/TA0003/) ``` username:prebuilds resource_type:api_key ``` Following [filter](https://coder.com/docs/admin/security/audit-logs#how-to-filter-audit-logs) can be used to list all *write* operations performed by the `prebuilds` user (including failed attempts to update various settings) ``` username:prebuilds action:write ``` ### Patched versions - [2.24.4](https://github.com/coder/coder/releases/tag/v2.24.4) - [2.25.2](https://github.com/coder/coder/releases/tag/v2.25.2) - [2.26.0](https://github.com/coder/coder/releases/tag/v2.26.0)

Source published

5 Sep 2025 20:19:58 UTC

Source modified

17 Sep 2025 17:42:08 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Publisher rating · HIGH

Coder vulnerable to privilege escalation could lead to a cross workspace compromise in github.com/coder/coder

Source published

17 Sep 2025 17:03:49 UTC

Source modified

3 Mar 2026 04:57:27 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.