ink! vulnerable to incorrect decoding of storage value when using DelegateCall

Exploitation

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

CVSS

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

EPSS

• CVE-2023-34449: 0.97% estimated exploitation activity in the next 30 days; percentile 61.84 (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.

Summary The return value when using delegate call mechanics, either through CallBuilder::delegate or inkenv::invokecontractdelegate, is being decoded incorrectly. Description Consider this minimal example: In this example we are executing the Callee code in the context of the Caller contract. This means we'll be using the storage values of the Caller contract. Running this code we expect the delegate call to return value as it was stored in the Caller contract. However, due to the reported bug a different value is returned (for the case of uints it is 256 times the expected value). Impact After conducting an analysis of the on-chain deployments of ink! contracts on Astar, Shiden, Aleph Zero, Amplitude and Pendulum, we have found that no contracts on those chains have been affected by the issue. This bug was related to the mechanics around decoding a call's return buffer, which was changed as part of https://github.com/paritytech/ink/pull/1450. Since this feature was only released in…

Published by the source

14 Jun 2023, 20:11 UTC

Last modified by the source

5 Nov 2023, 05:03 UTC

Source last checked

26 Oct 2026, 15:37 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-853p-5678-hv8f

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# Patch Next advisory brief: CVE-2023-34449

Advisory: ink! vulnerable to incorrect decoding of storage value when using `DelegateCall`
IDs: CVE-2023-34449, GHSA-853p-5678-hv8f
Record: https://patchnext.com/advisories/cve-2023-34449 (revision 1, source checked 26 Oct 2026, 15:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ink 4.2.1; ink_env 4.2.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io ink: affected >= 4.0.0, < 4.2.1; fixed in 4.2.1
- crates.io ink_env: affected >= 4.0.0, < 4.2.1; fixed in 4.2.1

## Suggested inspection (read-only)
- crates.io ink: check the installed version with your package manager.
- crates.io ink_env: 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 ink, ink_env.
- 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-853p-5678-hv8f (GitHub-reviewed advisory GHSA-853p-5678-hv8f lists affected ranges: crates.io ink >=4.0.0 =4.0.0 <4.2.1)

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