Vulnerability · Published Dec 8, 2023 · Assigned by Dfinity

CVE-2023-6245Infinite decoding loop through specially crafted payload

High 7.5

In plain English

A high-severity infinite loop in Candid from Internet Computer. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 69% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)1.2%top 31.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

The Candid library causes a Denial of Service while parsing a specially crafted payload with 'empty' data type. For example, if the payload is `record { * ; empty }` and the canister interface expects `record { * }` then the Rust candid decoder treats empty as an extra field required by the type. The problem with the type empty is that the candid Rust library wrongly categorizes empty as a recoverable error when skipping the field and thus causing an infinite decoding loop. Canisters using affected versions of candid are exposed to denial of service by causing the decoding to run indefinitely until the canister traps due to reaching maximum instruction limit per execution round. Repeated exposure to the payload will result in degraded performance of the canister. Note: Canisters written in Motoko are unaffected.

Affected products (as reported)

Vendor	Product	Versions
Internet Computer	Candid	0.9.0 – before 0.9.10

Weakness: CWE-835, CWE-1288, CWE-168, CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

In plain English

Official description

Affected products (as reported)

References