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

Source: https://junglewise.ai/threats/cve-2026-46384-iskorotkov-avro-integer-overflow-and-narrowing-in-decoder  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-29. Updated: 2026-05-29  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/github-com-hamba-avro-v2), [github.com/iskorotkov/avro/v2 (Go)](https://junglewise.ai/threats/technologies/github-com-iskorotkov-avro-v2), [Hamba Avro/V2](https://junglewise.ai/threats/technologies/avro-v2). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Hamba](https://junglewise.ai/threats/vendors/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

  ```sh
  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

- [https://github.com/iskorotkov/avro/security/advisories/GHSA-mc57-h6j3-3hmv](https://github.com/iskorotkov/avro/security/advisories/GHSA-mc57-h6j3-3hmv)

## Related threats

- [GO-2026-5048 - Denial of service via unbounded map allocations in github.com/iskorotkov/avro/v2 and github.com/hamba/avro/v2](https://junglewise.ai/threats/go-2026-5048-denial-of-service-via-unbounded-map-allocations-in-github-046da6cd)
- [iskorotkov/avro CPU exhaustion in array and map decoders](https://junglewise.ai/threats/cve-2026-46385-iskorotkov-avro-cpu-exhaustion-in-array-and-map-decoders)
- [iskorotkov/avro memory exhaustion in map decoder](https://junglewise.ai/threats/iskorotkov-avro-memory-exhaustion-in-map-decoder-7795edd3)
- [GO-2023-1930 - Unrestricted memory consumption in github.com/hamba/avro](https://junglewise.ai/threats/cve-2023-37475-avro-vulnerable-to-denial-of-service-via-attacker-controlled)