Coder: Zip upload decompression lacks aggregate size limit, enabling denial of service
Coder allows organizations to provision remote development environments via Terraform. Starting in version 2.17.0 and prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, `POST /api/v2/files` converts zip uploads to tar in memory via `CreateTarFromZip`, which enforced a per-entry size limit but no aggregate limit on total decompressed output, writing to an unbounded in-memory buffer. Exploitation requires authenticated file-upload access and the impact is limited to availability (denial of service). The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 adds a metadata preflight check that sums projected entry sizes and a streaming writer that enforces the aggregate limit during decompression. As a workaround, restrict file-upload permissions to trusted users or place a reverse proxy with request-body size limits in front of `coderd`.
- Published
- Jul 7, 2026
- Updated
- Jul 8, 2026
- EPSS
- 0.6% · 47th percentile
- CWE
- CWE-409
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Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 6.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| coder | coder | cpe:2.3:a:coder:coder |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- coder coder2.17.0 and later · before 2.29.17
- coder coder2.30.0 and later · before 2.32.7
- coder coder2.33.0 and later · before 2.33.8
- coder coder2.34.0 and later · before 2.34.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
coder coder
- >= 2.34.0, < 2.34.2, >= 2.33.0, < 2.33.8, >= 2.30.0, < 2.32.7, >= 2.17.0, < 2.29.17affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Go | github.com/coder/coder | all versions | — |
| Go | github.com/coder/coder/v2 | from 2.17.0 · before 2.29.17 | 2.29.17 |
| Go | github.com/coder/coder/v2 | from 2.30.0 · before 2.32.7 | 2.32.7 |
| Go | github.com/coder/coder/v2 | from 2.33.0 · before 2.33.8 | 2.33.8 |
| Go | github.com/coder/coder/v2 | from 2.34.0 · before 2.34.2 | 2.34.2 |
Same product
coder: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-46354Coder: PKCS#7 signature bypass in Azure instance identity allows unauthenticated agent token theft36Monitor
- CVE-2026-44454Coder vulnerable to workspace auto-creation via crafted URL parameters without user consent36Monitor
- CVE-2026-55429Coder's workspace app upsert allows cross-workspace agent rebinding via user-controlled app ID34Monitor
- CVE-2026-63443Coder: Workspace agent API insecure redirect handling allowed cross-agent file read and write33Monitor
- CVE-2026-55427Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`33Monitor
- CVE-2026-55428Coder: Route hijacking through lack of validation of agent-supplied AllowedIPs in tailnet coordinator32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Go:github.com/coder/coder/v2 | 2.29.17 | Package registry (OSV) |
| Go:github.com/coder/coder/v2 | 2.32.7 | Package registry (OSV) |
| Go:github.com/coder/coder/v2 | 2.33.8 | Package registry (OSV) |
| Go:github.com/coder/coder/v2 | 2.34.2 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-409 · Improper Handling of Highly Compressed Data (Data Amplification)CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/coder/coder/pull/25877
- github.com/coder/coder/releases/tag/v2.29.17
- github.com/coder/coder/releases/tag/v2.32.7
- github.com/coder/coder/releases/tag/v2.33.8
- github.com/coder/coder/releases/tag/v2.34.2
- github.com/coder/coder/security/advisories/GHSA-2mg2-p7r7-g27f
Vendor advisories and official records. Exploit/PoC links are deliberately left out.