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Vulnerability · Published May 29, 2026 · Assigned by GitHub_M

CVE-2026-46384iskorotkov/avro: Integer Overflow in Avro Decoder

High 7.5

In plain English

A high-severity integer overflow in avro from iskorotkov. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 53.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

iskorotkov/avro is a fast Go Avro codec. Prior to 2.33.0, several Avro decoder paths read attacker-controlled 64-bit values from the wire format and either narrowed them to platform-sized int before bounds-checking, or summed them with overflow-prone signed-int arithmetic. On 32-bit targets (GOARCH=386, arm, mips, wasm, etc.), the truncation paths can silently bypass byte-slice limits, select the wrong union branch, or hit the OCF negative-make panic via wrap. Three sub-issues are not 32-bit-specific: cumulative-size arithmetic overflow in arrayDecoder.Decode / mapDecoder.Decode / mapDecoderUnmarshaler.Decode (wraps at math.MaxInt64 on amd64 / arm64 and bypasses MaxSliceAllocSize / MaxMapAllocSize), math.MinInt negation in block-header handling, and make([]byte, size) with a negative size in OCF block reads — all three panic or bypass caps on any platform, giving an attacker a denial-of-service primitive there. This vulnerability is fixed in 2.33.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/hamba/avro/v2no fix listedGO-2026-5047
Gogithub.com/iskorotkov/avro/v22.33.0GHSA-mc57-h6j3-3hmv
Gogithub.com/iskorotkov/avro/v22.33.0GO-2026-5047

Affected products (as reported)

VendorProductVersions
iskorotkov avro < 2.33.0

Weakness: CWE-190 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References