CVE-2026-55079: Coder uncontrolled memory allocation in provisionersdk

CVE-2026-55079 · Severity: medium · CVSS 4.9 · Published 2026-07-08

Coder, a platform used to manage remote development environments, is vulnerable to a denial-of-service attack. An attacker with high-level permissions could send a specially crafted message that forces the system to attempt an impossible memory allocation, causing the entire Coder service to crash. This could disrupt development operations and prevent teams from accessing their remote workspaces.

Technologies: Coder, github.com/coder/coder (Go), github.com/coder/coder/v2 (Go). Vendors: Coder, Go.

Quick answers

Is CVE-2026-55079 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55079 being exploited in the wild.
How severe is CVE-2026-55079?
Medium severity, with a CVSS score of 4.9, published 8 July 2026.
Which products and versions are affected?
Coder >= 2.24.0, < 2.29.17; >= 2.30.0, < 2.32.7; >= 2.33.0, < 2.33.8; >= 2.34.0, < 2.34.2, >= 2.34.0, < 2.34.2; >= 2.33.0, < 2.33.8; >= 2.30.0, < 2.32.7; >= 2.24.0, < 2.29.17; github.com/coder/coder (Go) SEMVER:introduced=0; github.com/coder/coder/v2 (Go) SEMVER:introduced=2.24.0,fixed=2.29.17,introduced=2.30.0,fixed=2.32.7,introduced=2.33.0,fixed=2.33.8,introduced=2.34.0,fixed=2.34.2, SEMVER:introduced=2.34.0,fixed=2.34.2.
Is there a fix for CVE-2026-55079?
Yes. github.com/coder/coder/v2 (Go): upgrade to 2.34.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55079 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-55079?
Check whether you run Coder, github.com/coder/coder (Go) or github.com/coder/coder/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/coder/coder/v2 (Go): upgrade to 2.34.2 or later
    go get github.com/coder/coder/v2@v2.34.2

Technical details

A vulnerability exists in Coder's `provisionersdk/proto/dataupload.go` within the `NewDataBuilder` function. The component fails to validate the `FileSize` field in a `DataUpload` message before using it to allocate a byte slice. While the DRPC wire limit is 4 MiB, the integer value for `FileSize` was unconstrained, allowing an attacker to request massive allocations (e.g., 1 TiB) that trigger an unrecoverable `runtime.throw` and crash the `coderd` process. This requires high privileges to exploit. The issue is fixed in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 by implementing a `MaxFileSize` limit of 100 MiB.

Affected products

  • Coder Coder >= 2.24.0, < 2.29.17; >= 2.30.0, < 2.32.7; >= 2.33.0, < 2.33.8; >= 2.34.0, < 2.34.2

Identifiers

  • CVE-2026-55079
  • GHSA-f962-qm93-mj4c
  • GO-2026-5911

Timeline

  • 2026-05-27: patched: Fix merged into main branch via PR #25710
  • 2026-06-11: advisory: Security releases v2.32.7 and v2.33.8 published
  • 2026-06-12: advisory: Security release v2.29.17 published
  • 2026-07-08: disclosed: CVE-2026-55079 published to NVD

References

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