# CVE-2026-65631: Inefficient Algorithmic Complexity in erlang-jose allows an unauthenticated remote attacker to cause a CPU-exhaustion denial of service by s


- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 26 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-65631, EEF-CVE-2026-65631, GHSA-3m45-vrpj-xmrq, UBUNTU-CVE-2026-65631

## What is CVE-2026-65631?

CVE-2026-65631 is a medium-severity vulnerability in potatosalad jose, published on 26 Oct 2026. 

### Official description

Inefficient Algorithmic Complexity in erlang-jose allows an unauthenticated remote attacker to cause a CPU-exhaustion denial of service by submitting a crafted RSA JSON Web Key.

When an application parses an untrusted JWK through the public jose_jwk:from_binary/1 or jose_jwk:from_map/1 API (or the Elixir wrappers JOSE.JWK.from_binary/1 and JOSE.JWK.from_map/1), an RSA private key that supplies d, e, and n but omits all Chinese Remainder Theorem parameters (p, q, dp, dq, qi) is routed into convert_sfm_to_crt/1, which tries to recover the missing primes by factoring the modulus. The three integers are read straight from the base64url input and are never validated as a real RSA key. When the modulus cannot be split into two factors (for example, when it is itself prime), the search loop convert_sfm_to_crt_find_p/6 performs a modular exponentiation over the attacker-sized modulus on every iteration and never succeeds. A single request of a few hundred bytes forces close to one CPU-second of work before an internal one-second watchdog kills the worker, and a larger modulus raises the cost further. By flooding such requests an attacker can saturate every scheduler and deny service, without credentials, a valid RSA key, or any special configuration.

This issue affects jose: from 1.7.7 before 1.11.13.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-65631?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jose` | Hex | From 1.7.7 | 1.11.13 |

## How do I fix CVE-2026-65631?

Upgrade jose to 1.11.13 or later.

## Is CVE-2026-65631 being exploited?

There is no known exploitation of CVE-2026-65631 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-65631 and fix it if it is affected.

What it is: CVE-2026-65631 is a medium-severity vulnerability in potatosalad jose, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-65631 in the wild and no public exploit code.

Affected packages and fixed versions:
- jose (Hex): affected from 1.7.7; fixed in 1.11.13

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-2026-65631/ (Markdown: https://insights.sbomify.com/CVE-2026-65631/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65631
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65631
- OSV: https://osv.dev/vulnerability/CVE-2026-65631

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-65631/
Summaries are generated and may contain mistakes; the official description above is the record.