# CVE-2026-86696: Unbounded atom creation from unsigned LogoutResponse status codes in esaml allows atom table exhaustion


- **Severity:** High 8.2 (`CVSS:4.0/AV:N/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
- **Fix available:** No
- **Published:** 22 Oct 2026
- **Updated:** 22 Oct 2026
- **Also known as:** EEF-CVE-2026-86696, GHSA-5rc7-wrfq-2h25

## What is CVE-2026-86696?

CVE-2026-86696 is a high-severity vulnerability in arekinath esaml, published on 22 Oct 2026. 

### Official description

Allocation of Resources Without Limits or Throttling vulnerability in esaml in dropbox esaml allows an unauthenticated attacker to exhaust the Erlang VM atom table and crash the node via unsigned LogoutResponse messages.

esaml:status_code_map/1 in src/esaml.erl maps any StatusCode value it does not recognize to an atom with list_to_atom/1 on the last colon-separated segment of the URN. esaml_sp:validate_logout_response/2 verifies a signature only when the message carries one, so an unsigned LogoutResponse posted to the single-logout endpoint reaches esaml:decode_logout_response/1 and mints one permanent atom per distinct status value. Atoms are never reclaimed and the VM caps the atom table at about one million entries, so an attacker who posts that many distinct values aborts the node.

This issue affects esaml: from 0.1.0 onward.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-86696?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `esaml` | Hex | From 0.1.0 | None |

## How do I fix CVE-2026-86696?

No fix has been published for CVE-2026-86696 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-86696 being exploited?

There is no known exploitation of CVE-2026-86696 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-86696 and fix it if it is affected.

What it is: CVE-2026-86696 is a high-severity vulnerability in arekinath esaml, published on 22 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-86696 in the wild and no public exploit code.

Affected packages and fixed versions:
- esaml (Hex): affected from 0.1.0; no fix listed

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-2026-86696/ (Markdown: https://insights.sbomify.com/CVE-2026-86696/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86696
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86696
- OSV: https://osv.dev/vulnerability/CVE-2026-86696

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86696/
Summaries are generated and may contain mistakes; the official description above is the record.