# CVE-2026-76236: stigmem before 0.9.0a12 Cross-Tenant BOLA via Tombstones

> Cross-tenant BOLA in stigmem-node allows attackers to hide or expose data across tenants via flawed tombstone mechanisms in multi-tenant deployments.

- **Severity:** High 7.2 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** GHSA-77m3-9g4f-372v, GHSA-x26h-xmv8-gxf7

## What is CVE-2026-76236?

CVE-2026-76236 is a high-severity missing authorization vulnerability in eidetic-labs stigmem-node, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

stigmem-node before 0.9.0a12 contains a cross-tenant broken object level authorization (BOLA) flaw in the RTBF (right-to-be-forgotten) tombstone mechanism. issue_tombstone defaulted the tenant to "default" instead of the caller's tenant, allowing deletion records to be written to the wrong tenant, and the read-suppression path (_get_tombstone_filter and the tombstone scope cache) lacked a tenant_id predicate, so tombstone suppression was applied tenant-blind across fact queries and provenance reads. As a result, a tenant's deletion could be attributed to the wrong tenant and tombstone suppression could either hide facts belonging to other tenants or fail to hide facts within the correct tenant, undermining data isolation and RTBF guarantees. The issue is exploitable only on multi-tenant deployments running the opt-in stigmem-plugin-multi-tenant; single-tenant deployments are unaffected. Fixed in 0.9.0a12.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-76236?

2 open source packages ship an affected version, including stigmem-node.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `stigmem-node` | PyPI | All versions | 0.9.0a12 |
| `stigmem-node` | PyPI | All versions | 0.9.0a12 |

## How do I fix CVE-2026-76236?

Upgrade stigmem-node to 0.9.0a12 or later.

## Is CVE-2026-76236 being exploited?

There is no known exploitation of CVE-2026-76236 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76236 and fix it if it is affected.

What it is: CVE-2026-76236 is a high-severity missing authorization vulnerability in eidetic-labs stigmem-node, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76236 in the wild and no public exploit code.

Affected packages and fixed versions:
- stigmem-node (PyPI): affected all versions; fixed in 0.9.0a12
- stigmem-node (PyPI): affected all versions; fixed in 0.9.0a12

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-76236/ (Markdown: https://insights.sbomify.com/CVE-2026-76236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76236
- OSV: https://osv.dev/vulnerability/CVE-2026-76236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-76236/
Summaries are generated and may contain mistakes; the official description above is the record.