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Vulnerability · Published May 29, 2026 · Assigned by GitHub_M

CVE-2026-46385iskorotkov/avro: CPU Exhaustion in Avro Decoder

High 7.5

In plain English

A high-severity uncontrolled resource consumption in avro from iskorotkov. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.6%top 50.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

iskorotkov/avro is a fast Go Avro codec. Prior to 2.33.0, the Avro array and map decoders looped over an attacker-controlled block-count value without checking the underlying reader's error state inside the loop body. Reader.ReadBlockHeader returns the count as a Go int, which is 64-bit on amd64 / arm64 targets — so a producer can declare a block of up to math.MaxInt64 (~9.2 × 10¹⁸) elements followed by EOF (or any truncated payload), and the decoder will attempt that many no-op iterations before propagating the error. The realistic ceiling is "indefinite until the worker is killed externally" — a single hostile payload pins a CPU core until the process is OOM-killed, deadline-cancelled, or terminated. Remote, unauthenticated denial-of-service. This vulnerability is fixed in 2.33.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/hamba/avro/v2no fix listedGO-2026-5046
Gogithub.com/iskorotkov/avro/v22.33.0GHSA-w8j3-pq8g-8m7w
Gogithub.com/iskorotkov/avro/v22.33.0GO-2026-5046

Affected products (as reported)

VendorProductVersions
iskorotkov avro < 2.33.0

Weakness: CWE-400, CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References