I don't know about 7-Zip specifically, but AV vendors use plenty of FOSS code. Here's some findings just from Google's P0 showing that Symantec[1], Bitdefender[

I don't know about 7-Zip specifically, but AV vendors use plenty of FOSS code. Here's some findings just from Google's P0 showing that Symantec[1], Bitdefender[2], Microsoft[3] and Avast[4] all use unrar in their products. It wouldn't be far-fetched to assume some might use 7-Zip for other archive formats. [1]: https://bugs.chromium.org/p/project-zero/issues/detail?id=810 https://bugs.chromium.org/p/project-zero/issues/detail?id=81... [2]: https://bugs.chromium.org/p/project-zero/issues/detail?id=1278 https://bugs.chromium.org/p/project-zero/issues/detail?id=12... [3]: https://bugs.chromium.org/p/project-zero/issues/detail?id=1543 https://bugs.chromium.org/p/project-zero/issues/detail?id=15... [4]: https://bugs.chromium.org/p/project-zero/issues/detail?id=575 https://bugs.chromium.org/p/project-zero/issues/detail?id=57...