How severe is CVE-2026-76243?

No CVSS score has been assigned to CVE-2026-76243 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-76243?

CVE-2026-76243 affects the following packages: stigmem-node (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-76243?

Update stigmem-node to 0.9.0a2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76243 is resolved across your whole dependency graph.

How do I detect CVE-2026-76243 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-2026-76243 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-76243 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-76243 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-2026-76243?

CVE-2026-76243 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 45th 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-2026-76243?

CVE-2026-76243 is classified as CWE-285 (CWE-285). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-76243 published, and has it been updated?

CVE-2026-76243 was published on August 19, 2026 and was last updated on September 26, 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-2026-76243 — stigmem-node

CVE-2026-76243 is a CWE-285 vulnerability in stigmem-node. A fix is available for stigmem-node — see the affected versions and patch details below.

stigmem before 0.9.0a2 Authentication Bypass via Disabled Auth

Also known asGHSA-fp6w-8wpg-74g5

Published

Aug 19, 2026

Updated

Sep 26, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
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-2026-76243.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs45th percentile — riskier than 45% 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

Impact

Stigmem nodes configured with authentication disabled could grant the anonymous identity broad read/write/federation capabilities if exposed outside a loopback-only local development environment. Impacted users are operators who intentionally disabled authentication while binding the node to a non-loopback URL.

Patches

Patched in 0.9.0a2. The node now refuses unauthenticated operation outside loopback-only local development.

Workarounds

Before upgrading, keep authentication enabled for all non-local deployments and do not expose nodes with authentication disabled to untrusted networks.

Upgrade

Upgrade to the patched release:

pip install --upgrade --pre stigmem-node

If developers install through the Stigmem meta-package instead, they should use the matching extra for their deployments, for example:

pip install --upgrade --pre 'stigmem[node]'

Resources

Release: https://github.com/eidetic-labs/stigmem/releases/tag/v0.9.0a2
Changelog: https://github.com/eidetic-labs/stigmem/blob/v0.9.0a2/CHANGELOG.md#L14-L35
Security policy and posture: https://github.com/eidetic-labs/stigmem/blob/v0.9.0a2/SECURITY.md

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`stigmem-node`	all versions	0.9.0a2`pip install --upgrade 'stigmem-node==0.9.0a2'`

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 0.9.0a2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76243 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Stigmem nodes configured with authentication disabled could grant the anonymous identity broad read/write/federation capabilities if exposed outside a loopback-only local development environment. Impacted users are operators who intentionally disabled authentication while binding the node to a non-loopback URL. ### Patches Patched in 0.9.0a2. The node now refuses unauthenticated operation outside loopback-only local development. ### Workarounds Before upgrading, keep authentication enabled for all non-local deployments and do not expose nodes with authentication disabled to untrus

O3 Security · Impact-Aware SCA

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CVE-2026-76243 — stigmem-node

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

Real-World Exposure

Description

Impact

Patches

Workarounds

Upgrade

Resources

Affected Packages

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2026-76243 in your dependencies?