CVE-2026-55079: Coder's unbounded memory allocation in provisioner file upload allows authenticated denial of service

July 6, 2026

NewDataBuilder in provisionersdk/proto/dataupload.go allocated a byte slice using the client-supplied FileSize from a DataUpload message without an upper-bound check. Although the DRPC wire limit is 4 MiB, the FileSize value itself was unconstrained

References

github.com/advisories/GHSA-f962-qm93-mj4c
github.com/coder/coder/pull/25710
github.com/coder/coder/security/advisories/GHSA-f962-qm93-mj4c
nvd.nist.gov/vuln/detail/CVE-2026-55079

Code Behaviors & Features

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