FuelVM is vulnerable to heap memory allocation re-use bug

Exploitation

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

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact A memory safety vulnerability was present in the Fuel Virtual Machine (FuelVM), where memory reads could bypass expected access controls. Specifically, when a smart contract performed a mload (or other opcodes which access memory) on memory that had been deallocated using ret, it was still able to access the old memory contents. This occurred because the memory region was not zeroed out or otherwise marked as invalid. As a result, smart contracts could potentially read sensitive data left over from other contracts if the same memory was reallocated, violating isolation guarantees between contracts and enabling unintended data leakage. All users running affected versions of FuelVM that relied on strict memory isolation between smart contracts were impacted. Patches The vulnerability was patched by modifying the FuelVM to ensure that memory deallocated with ret was zeroed out or made inaccessible. The fix was included in FuelVM version v0.60.1 and back-ported to v0.59.3. This…

Published by the source

8 Oct 2025, 12:43 UTC

Last modified by the source

8 Oct 2025, 12:43 UTC

Source last checked

26 Oct 2026, 15:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2pgj-5cv2-6xxw

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# Patch Next advisory brief: GHSA-2pgj-5cv2-6xxw

Advisory: FuelVM is vulnerable to heap memory allocation re-use bug
IDs: GHSA-2pgj-5cv2-6xxw
Record: https://patchnext.com/advisories/ghsa-2pgj-5cv2-6xxw (revision 1, source checked 26 Oct 2026, 15:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: fuel-vm 0.60.1, 0.59.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io fuel-vm: affected < 0.59.3; >= 0.60.0, < 0.60.1; fixed in 0.59.3, 0.60.1

## Suggested inspection (read-only)
- crates.io fuel-vm: 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 fuel-vm.
- 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-2pgj-5cv2-6xxw (GitHub-reviewed advisory GHSA-2pgj-5cv2-6xxw lists affected ranges: crates.io fuel-vm >=0 =0.60.0 <0.60.1)

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