Bugsink is a self-hosted error tracking tool. In versions prior to 2.0.5, brotli "bombs" (highly compressed brotli streams, such as many zeros) can be sent to the server. Since the server will attempt to decompress these streams before applying various maximums, this can lead to exhaustion of the available memory and thus a Denial of Service. This can be done if the `DSN` is known, which it is in many common setups (JavaScript, Mobile Apps). The issue is patched in Bugsink version `2.0.5`. The vulnerability is similar to, but distinct from, another brotli-related problem in Bugsink, GHSA-rrx3-2x4g-mq2h/CVE-2025-64509.
https://github.com/google/brotli/releases/tag/v1.2.0
https://github.com/google/brotli/pull/1234
https://github.com/google/brotli/issues/1375
https://github.com/google/brotli/issues/1327
https://github.com/google/brotli/commit/67d78bc41db1a0d03f2e763497748f2f69946627
https://github.com/bugsink/bugsink/security/advisories/GHSA-fc2v-vcwj-269v
https://github.com/bugsink/bugsink/pull/266
https://github.com/bugsink/bugsink/commit/3f65544aab3ad5303d97009136640de97b0676a5