Vulnerability · Published Jul 7, 2026 · Assigned by GitHub_M

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

Medium 4.9

In plain English

A medium-severity security flaw in coder from coder. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.9Medium

Exploit odds (30 days)0.6%top 50.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Coder allows organizations to provision remote development environments via Terraform. Starting in version 2.24.0 and prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, `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. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates `FileSize` against an upper bound (`MaxFileSize = 100 MiB`) before allocation. As a workaround, restrict access to the provisioner daemon serve endpoint to trusted provisioner daemon service accounts.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/coder/coder	no fix listed	GO-2026-5911
Go	github.com/coder/coder/v2	2.34.2	GHSA-f962-qm93-mj4c
Go	github.com/coder/coder/v2	2.33.8	GHSA-f962-qm93-mj4c
Go	github.com/coder/coder/v2	2.32.7	GHSA-f962-qm93-mj4c
Go	github.com/coder/coder/v2	2.29.17	GHSA-f962-qm93-mj4c
Go	github.com/coder/coder/v2	2.29.17, 2.32.7, 2.33.8, 2.34.2	GO-2026-5911

Affected products (as reported)

Vendor	Product	Versions
coder	coder	>= 2.34.0, < 2.34.2>= 2.33.0, < 2.33.8>= 2.30.0, < 2.32.7>= 2.24.0, < 2.29.17

Weakness: CWE-789 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/coder/coder/security/advisories/GHSA-f962-qm93-mj4c x_refsource_CONFIRM
https://github.com/coder/coder/pull/25710 x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.29.17 x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.32.7 x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.33.8 x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.34.2 x_refsource_MISC