CVE-2019-3556
One of those request handlers, dump-pcre-cache, can be used to output cached regular expressions from the current execution context into a file.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.79%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
HHVM supports the use of an "admin" server which accepts administrative requests over HTTP. One of those request handlers, dump-pcre-cache, can be used to output cached regular expressions from the current execution context into a file. The handler takes a parameter which specifies where on the filesystem to write this data. The parameter is not validated, allowing a malicious user to overwrite arbitrary files where the user running HHVM has write access. This issue affects HHVM versions prior to 4.56.2, all versions between 4.57.0 and 4.78.0, as well as 4.79.0, 4.80.0, 4.81.0, 4.82.0, and 4.83.0.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- EPSS
- 1.79% probability · 78th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Affected
- facebook/hhvm
- Source
- cve-assign@fb.com
EPSS 1.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/facebook/hhvm/commit/abe0b29e4d3a610f9bc920b8be4ad8403364c2d4Patch, Third Party Advisory
- https://hhvm.com/blog/2020/11/12/security-update.htmlVendor Advisory
- https://www.facebook.com/security/advisories/cve-2019-3556Broken Link
- https://github.com/facebook/hhvm/commit/abe0b29e4d3a610f9bc920b8be4ad8403364c2d4Patch, Third Party Advisory
- https://hhvm.com/blog/2020/11/12/security-update.htmlVendor Advisory
- https://www.facebook.com/security/advisories/cve-2019-3556Broken Link
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.