CVE-2026-46384: iskorotkov avro integer overflow and narrowing in decoder

CVE-2026-46384 · Severity: high · CVSS 7.5 · Published 2026-05-29

The iskorotkov/avro library, a tool used by Go applications to process Avro-formatted data, contains several integer handling flaws. An attacker can send a specially crafted data stream that causes the application to crash or consume excessive resources, leading to a denial-of-service. In some specific configurations on 32-bit systems, this could also lead to data being processed incorrectly by selecting the wrong data types during decoding.

Technologies: github.com/hamba/avro/v2 (Go), github.com/iskorotkov/avro/v2 (Go), Hamba Avro/V2. Vendors: Go, Hamba.

Quick answers

Is CVE-2026-46384 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-46384 being exploited in the wild.
How severe is CVE-2026-46384?
High severity, with a CVSS score of 7.5, published 29 May 2026.
Which products and versions are affected?
github.com/hamba/avro/v2 (Go) SEMVER:introduced=0; github.com/iskorotkov/avro/v2 (Go) < 2.33.0, SEMVER:introduced=0,fixed=2.33.0; Hamba Avro/V2 < 2.33.0.
Is there a fix for CVE-2026-46384?
Yes. github.com/iskorotkov/avro/v2 (Go): upgrade to 2.33.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-46384 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-46384?
Check whether you run github.com/hamba/avro/v2 (Go), github.com/iskorotkov/avro/v2 (Go) or Hamba Avro/V2 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/iskorotkov/avro/v2 (Go): upgrade to 2.33.0 or later
    go get github.com/iskorotkov/avro/v2@v2.33.0

Technical details

Multiple integer-related vulnerabilities exist in the Avro decoder. On 32-bit platforms, 64-bit values from the wire format are narrowed to 32-bit integers before bounds-checking, allowing attackers to bypass 'MaxSliceAllocSize' and 'MaxByteSliceSize' limits. Additionally, cumulative-size arithmetic in array and map decoders is prone to signed integer overflow on all platforms, where a running total can wrap to a negative value and bypass allocation caps. Other sub-issues include a panic caused by negating 'math.MinInt' in block-header handling and a 'make' panic when processing negative block sizes in Object Container Files (OCF). These flaws collectively provide a denial-of-service primitive and, in the case of union index narrowing, potential logic errors in data interpretation. The issues are fixed in version 2.33.0.

Affected products

  • iskorotkov avro < 2.33.0
  • hamba avro/v2 <= 2.31.0

Identifiers

  • CVE-2026-46384
  • GHSA-mc57-h6j3-3hmv
  • GO-2026-5047

Timeline

  • 2026-05-11: advisory: GitHub advisory published by maintainer
  • 2026-05-29: disclosed: CVE-2026-46384 published

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.