kora-lib: Unrecognized Instruction Types Create Empty Stubs That Bypass Fee Payer Policy

Exploitation

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

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/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.

Summary When inner CPI instructions use instruction types not recognized by Kora's parser (including Token-2022 extension instructions like ConfidentialTransfer, TransferFeeExtension::WithdrawWithheldTokens, etc.), they are reconstructed as stub instructions with empty accounts and empty data. These stubs fail deserialization during fee payer policy validation and are silently skipped, meaning any fee payer usage within those instructions goes completely unchecked. Severity Medium Affected Component - File: crates/lib/src/transaction/instructionutil.rs - Functions: reconstructsysteminstruction(), reconstructspltokeninstruction() - Lines: 750–753, 1187–1189 Root Cause The instruction reconstruction functions have a catch-all = arm for unrecognized instruction types that creates a stub CompiledInstruction with the correct programidindex but empty accounts and empty data. When this stub reaches the fee payer policy parsing (parsesysteminstructions / parsetokeninstructions),…

Published by the source

12 Mar 2026, 14:50 UTC

Last modified by the source

12 Mar 2026, 14:50 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-x442-m7cc-hr92

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# Patch Next advisory brief: GHSA-x442-m7cc-hr92

Advisory: kora-lib: Unrecognized Instruction Types Create Empty Stubs That Bypass Fee Payer Policy
IDs: GHSA-x442-m7cc-hr92
Record: https://patchnext.com/advisories/ghsa-x442-m7cc-hr92 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: kora-lib 2.0.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io kora-lib: affected < 2.0.5; fixed in 2.0.5

## Suggested inspection (read-only)
- crates.io kora-lib: 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 kora-lib.
- 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-x442-m7cc-hr92 (GitHub-reviewed advisory GHSA-x442-m7cc-hr92 lists affected ranges: crates.io kora-lib >=0 <2.0.5)

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