CVE-2026-27695 zae-limiter: DynamoDB hot partition throttling enables per-entity Denial of Service
Attackers can cause denial of service for specific entities by exploiting DynamoDB partition throttling in the zae-limiter library.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27695?
CVE-2026-27695 is a medium-severity denial of service vulnerability in zeroae zae-limiter, published on 25 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-27695?
3 open source packages ship an affected version, including zae-limiter. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
zae-limiter PyPI | All versions | 0.10.1 |
zae-limiter PyPI | All versions | 0.10.1 |
zae-limiter PyPI | All versions | 0.10.1 |
Products include Zeroae Zae-Limiter.
How do I fix CVE-2026-27695?
Upgrade zae-limiter to 0.10.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-27695 being exploited?
There is no known exploitation of CVE-2026-27695 in the wild and no public exploit code.
Sources
Also known as GHSA-76rv-2r9v-c5m6, PYSEC-2026-3434.