# CVE-2026-46385: iskorotkov/avro CPU exhaustion in array and map decoders

Source: https://junglewise.ai/threats/cve-2026-46385-iskorotkov-avro-cpu-exhaustion-in-array-and-map-decoders  
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-2026-46385 · Severity: high · CVSS 7.5 · Published 2026-05-29

The iskorotkov/avro library, a high-performance Go-based tool for processing Avro data, is vulnerable to a denial-of-service attack. An attacker can send a specially crafted data payload that causes the library to enter an extremely long processing loop, effectively freezing the application and consuming 100% of a CPU core. This can lead to service outages or system crashes if multiple malicious requests are processed simultaneously.

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-2026-46385 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-46385 being exploited in the wild.

**How severe is CVE-2026-46385?** 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-2026-46385?** 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-2026-46385 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-46385?** 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

The vulnerability exists in the Avro array and map decoders within `codec_skip.go` and `reader_generic.go`. When decoding blocks, the library reads an attacker-controlled block-count value (up to math.MaxInt64) and iterates that many times. If the underlying reader encounters an error (such as EOF from a truncated payload), the inner decoder short-circuits, but the outer loop continues to iterate without checking the reader's error state. On 64-bit systems, this results in up to 9.2 quintillion no-op iterations, pinning a CPU core indefinitely. The issue is fixed in version 2.33.0 by adding an error check inside the loop body to terminate execution immediately upon the first inner-decode failure.

## Affected products

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

## Identifiers

- CVE-2026-46385
- GHSA-w8j3-pq8g-8m7w
- GO-2026-5046

## Timeline

- 2026-05-11: advisory: GitHub Security Advisory published by iskorotkov
- 2026-05-29: disclosed: CVE-2026-46385 published to NVD

## References

- [https://github.com/iskorotkov/avro/security/advisories/GHSA-w8j3-pq8g-8m7w](https://github.com/iskorotkov/avro/security/advisories/GHSA-w8j3-pq8g-8m7w)

## 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 integer overflow and narrowing in decoder](https://junglewise.ai/threats/cve-2026-46384-iskorotkov-avro-integer-overflow-and-narrowing-in-decoder)
- [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)