CVE-2023-47163 Remarshal expands YAML alias nodes unlimitedly, hence Remarshal is vulnerable to Billion Laughs Attack
Attackers can cause denial of service by providing malicious YAML files with unlimited alias expansion to applications using Remarshal.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-47163?
CVE-2023-47163 is a high-severity denial of service vulnerability in Remarshal-project Remarshal, published on 13 Nov 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Remarshal prior to v0.17.1 expands YAML alias nodes unlimitedly, hence Remarshal is vulnerable to Billion Laughs Attack. Processing untrusted YAML files may cause a denial-of-service (DoS) condition.
Weakness: CWE-674
Which versions are affected by CVE-2023-47163?
3 open source packages ship an affected version, including remarshal. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
remarshal PyPI | All versions | 0.17.1 |
remarshal PyPI | All versions | 0.17.1 |
remarshal PyPI | All versions | 0.17.1 |
Products include Remarshal Project Remarshal.
How do I fix CVE-2023-47163?
Upgrade remarshal to 0.17.1 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-2023-47163 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-47163 exists.
Sources
Also known as GHSA-gw7g-qr8w-3448, PYSEC-2023-236.