go-ipld-prime: DAG-CBOR decoder unbounded memory allocation from CBOR headers

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.2 · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-35480: 0.16% estimated exploitation activity in the next 30 days; percentile 4.75 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

The DAG-CBOR decoder uses collection sizes declared in CBOR headers as Go preallocation hints for maps and lists. The decoder does not cap these size hints or account for their cost in its allocation budget, allowing small payloads to cause excessive memory allocation. A CBOR map or list header can declare an arbitrarily large number of entries, causing the decoder to preallocate proportionally large backing structures before any entries are actually read. Because the allocation budget is only decremented as entries are decoded (not when sizes are declared), this cost is effectively invisible to the budget system. This is compounded by nesting: each level of a nested structure triggers its own unchecked preallocation while consuming minimal budget (one entry per parent level), so a payload under 100 bytes with 10 levels of nesting can cause over 9GB of allocation. Schema-free decoding (i.e. using basicnode.Prototype.Any) allows arbitrary nesting depth. Schema-bound decoding limits…

Published by the source

6 Apr 2026, 23:08 UTC

Last modified by the source

7 Apr 2026, 20:00 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-378j-3jfj-8r9f

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-35480

Advisory: go-ipld-prime: DAG-CBOR decoder unbounded memory allocation from CBOR headers
IDs: CVE-2026-35480, GHSA-378j-3jfj-8r9f
Record: https://patchnext.com/advisories/cve-2026-35480 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/ipld/go-ipld-prime 0.22.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/ipld/go-ipld-prime: affected < 0.22.0; fixed in 0.22.0

## Suggested inspection (read-only)
- Go github.com/ipld/go-ipld-prime: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/ipld/go-ipld-prime.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-378j-3jfj-8r9f (GitHub-reviewed advisory GHSA-378j-3jfj-8r9f lists affected ranges: Go github.com/ipld/go-ipld-prime >=0 <0.22.0)

Commands are suggestions: review each one before running it.