CVE-2020-1898 Denial of service in HHVM

What is CVE-2020-1898?

CVE-2020-1898 is a high-severity denial of service vulnerability in Facebook HHVM, published on 11 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The fb_unserialize function did not impose a depth limit for nested deserialization. That meant a maliciously constructed string could cause deserialization to recurse, leading to stack exhaustion. This issue affected HHVM prior to v4.32.3, between versions 4.33.0 and 4.56.0, 4.57.0, 4.58.0, 4.58.1, 4.59.0, 4.60.0, 4.61.0, 4.62.0.

Weakness: CWE-674

Which versions are affected by CVE-2020-1898?

It affects 1 product.

Products include Facebook Hhvm.

How do I fix CVE-2020-1898?

No fix has been published for CVE-2020-1898 yet. Limit exposure of the affected software until one is available.

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-2020-1898 being exploited?

There is no known exploitation of CVE-2020-1898 in the wild and no public exploit code.

Other vulnerabilities in Facebook HHVM

• CVE-2022-36937 HHVM 4.172.0 and all prior versions use TLS 1.0 for secure connections when handling tls:// URLs in the stream extension. Critical 9.8
• CVE-2020-1900 Use after free in HHVM Critical 9.8
• CVE-2020-1916 Integer overflow in HHVM Critical 9.8
• CVE-2020-1917 Memory corruption in HHVM Critical 9.8
• CVE-2021-24025 Integer overflow in HHVM Critical 9.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-86q4-p3xc-6m2h, UBUNTU-CVE-2020-1898.