CVE-2020-1917 Memory corruption in HHVM

What is CVE-2020-1917?

CVE-2020-1917 is a critical memory corruption vulnerability in Facebook HHVM, published on 10 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

xbuf_format_converter, used as part of exif_read_data, was appending a terminating null character to the generated string, but was not using its standard append char function. As a result, if the buffer was full, it would result in an out-of-bounds write. This issue affects HHVM versions prior to 4.56.3, all versions between 4.57.0 and 4.80.1, all versions between 4.81.0 and 4.93.1, and versions 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0.

Weakness: CWE-787, CWE-122

Which versions are affected by CVE-2020-1917?

It affects 1 product.

Products include Facebook Hhvm.

How do I fix CVE-2020-1917?

No fix has been published for CVE-2020-1917 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2020-1917 being exploited?

There is no known exploitation of CVE-2020-1917 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-2021-24025 Integer overflow in HHVM Critical 9.8
• CVE-2016-1000004 Other in n/a Critical 9.8

Sources

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

Also known as GHSA-gf82-22g8-prc5, UBUNTU-CVE-2020-1917.