How severe is CVE-2026-76238?

No CVSS score has been assigned to CVE-2026-76238 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-76238?

CVE-2026-76238 affects the following packages: stigmem-node (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-76238?

Update stigmem-node to 0.9.0a12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76238 is resolved across your whole dependency graph.

How do I detect CVE-2026-76238 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for stigmem-node, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-76238 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-76238 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-76238 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-76238?

CVE-2026-76238 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 30th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-76238?

CVE-2026-76238 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-76238 published, and has it been updated?

CVE-2026-76238 was published on August 19, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-76238 — stigmem-node

Fix: eidetic-labs/stigmem#728

CVE-2026-76238 is a CWE-863 vulnerability in stigmem-node. A fix is available for stigmem-node — see the affected versions and patch details below.

stigmem before 0.9.0a12 Cross-Tenant BOLA via decay sweep

Also known asGHSA-6gqw-jqv7-v88m

Published

Aug 19, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-76238.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs30th percentile — riskier than 30% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍stigmem-node

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

On a multi-tenant stigmem node, a caller holding a write credential for one tenant can run a decay sweep that acts on every tenant's facts. The candidate-selection queries in lifecycle/decay.py (_select_ttl_candidates, _select_confidence_candidates) carried no tenant_id predicate, and the caller's tenant was not threaded into the sweep or its async worker (run_decay_sweep / _decay_job_worker), reached via POST /v1/decay/sweep.

Impact

A sweep with ttl_seconds=0 expires all tenants' facts — cross-tenant data destruction (integrity and availability). A dry_run sweep returns a global candidate count, acting as a cross-tenant existence/volume oracle (information disclosure).

Affected configurations

This is a cross-tenant break. It is exploitable only on deployments running the opt-in stigmem-plugin-multi-tenant (multiple tenants on one node). A default single-tenant node has only tenant="default" — there is no second tenant to cross — so it is not exploitable on default deployments. The rating is HIGH for the multi-tenant deployments the plugin exists to isolate.

Patches

Fixed in 0.9.0a12 (PR #728): identity.tenant_id is threaded into run_decay_sweep and _decay_job_worker, and AND tenant_id = ? was added to the candidate selectors and the graph-sync. A tenant-B sweep now leaves tenant-A facts untouched, and dry_run counts only the caller's tenant. The check_fact_query_tenant_scope.py CI guard was extended to scan lifecycle/ so this class cannot silently regress.

Workarounds

None other than upgrading to 0.9.0a12. Single-tenant deployments are unaffected.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`stigmem-node`	all versions	0.9.0a12`pip install --upgrade 'stigmem-node==0.9.0a12'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for stigmem-node, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update stigmem-node to 0.9.0a12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76238 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Summary On a multi-tenant stigmem node, a caller holding a `write` credential for **one** tenant can run a decay sweep that acts on **every** tenant's facts. The candidate-selection queries in `lifecycle/decay.py` (`_select_ttl_candidates`, `_select_confidence_candidates`) carried no `tenant_id` predicate, and the caller's tenant was not threaded into the sweep or its async worker (`run_decay_sweep` / `_decay_job_worker`), reached via `POST /v1/decay/sweep`. ### Impact A sweep with `ttl_seconds=0` expires **all tenants'** facts — cross-tenant data destruction (integrity and availability).

O3 Security · Impact-Aware SCA

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