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VulnerabilityPublished

mpp vulnerable to Gas Draining with access list

Affects mppSource GCVE Database

0

CVSS 6.9 Medium : upgrade to 0.6.0 when convenient.

Data as of 26 Sep 2026, 05:04 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 0.6.0
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

What to do

Upgrade mpp to 0.6.0.

Affected software

ProductAffectedFixed in
HexmppAffected
  • >=0.2.0 <0.6.0
Fixed in
  • 0.6.0

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AI-suggested

A patch is available for this vulnerability. Users should apply the official fix to ensure the server properly validates or sanitizes client-supplied access lists before cosigning fee-payer transactions. Until patched, the server remains vulnerable to inflated gas costs via crafted access lists.

Description

The mpp Elixir 0.4.0 server, when acting as the fee payer, copies client-supplied EIP-2930 access lists directly into cosigned fee-payer transactions without validation. This allows an attacker to inflate transaction fees by including fabricated access list entries, causing the fee-payer to pay significantly higher gas costs without additional on-chain work. The attack can increase gas costs by approximately 7.4 times, severely impacting operational costs and profit margins for low-cost transactions.

References

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