# CVE-2026-81319: Unsafe deserialization of decrypted terms enables node DoS in AshCloak

> An attacker can crash the application by sending crafted encrypted data that triggers unsafe deserialization, causing resource exhaustion.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** EEF-CVE-2026-81319, GHSA-rc26-mrm2-6pf9

## What is CVE-2026-81319?

CVE-2026-81319 is a medium-severity unsafe deserialization vulnerability in ash-project ash_cloak, published on 30 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Deserialization of Untrusted Data vulnerability in ash-project ash_cloak allows an attacker who can influence the bytes of an encrypted column to crash the BEAM node, by triggering unbounded atom creation or a decompression bomb during decryption.

AshCloak.Calculations.Decrypt decodes the decrypted binary with Ash.Helpers.non_executable_binary_to_term/1 without the :safe option, so atoms in the payload are interned during the decode and never garbage collected, and the term format's compressed form is inflated transparently. vault.decrypt!() is the only barrier and stops tampering only for an authenticated cipher. Cloak also ships the unauthenticated AES.CTR, whose ciphertext an attacker who knows their own plaintext can XOR into any same-length payload without the key, so an ordinary read of the forged column reaches the decoder. A few hundred kilobytes of distinct atoms exhausts the atom table, or a small compressed payload inflates to gigabytes.

This issue affects ash_cloak: from 0.1.0 before 0.4.0.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-81319?

1 open source package ship an affected version, including ash_cloak.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash_cloak` | Hex | From 0.1.0 | 0.4.0 |

## How do I fix CVE-2026-81319?

Upgrade ash_cloak to 0.4.0 or later.

## Is CVE-2026-81319 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81319 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81319 and fix it if it is affected.

What it is: CVE-2026-81319 is a medium-severity unsafe deserialization vulnerability in ash-project ash_cloak, published on 30 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81319 exists.

Affected packages and fixed versions:
- ash_cloak (Hex): affected from 0.1.0; fixed in 0.4.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-81319/ (Markdown: https://insights.sbomify.com/CVE-2026-81319/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81319
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81319
- OSV: https://osv.dev/vulnerability/CVE-2026-81319

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-81319/
Summaries are generated and may contain mistakes; the official description above is the record.