CVE-2026-46384
Deferred Deferred - Pending Action
Integer Overflow in Iskorotkov Avro Go Codec

Publication date: 2026-05-29

Last updated on: 2026-05-29

Assigner: GitHub, Inc.

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.
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Meta Information
Published
2026-05-29
Last Modified
2026-05-29
Generated
2026-06-19
AI Q&A
2026-05-30
EPSS Evaluated
2026-06-18
NVD
CVE-2026-46384
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
iskorotkov avro to 2.33.0 (exc)
iskorotkov avro 2.33.0
iskorotkov avro v2.33.0
hamba avro to 2.31.0 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
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Compliance Impact

The vulnerability described in CVE-2026-46384 primarily leads to denial-of-service conditions and potential logic errors due to integer overflow and unsafe memory operations in the Avro decoder library.

There is no direct information in the provided context or resources about how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

Executive Summary

CVE-2026-46384 is an integer overflow vulnerability in the Avro decoder library used in Go. The issue occurs when the decoder reads attacker-controlled 64-bit values from the Avro wire format and either narrows them to platform-sized integers before performing bounds-checking or performs arithmetic that can overflow. On 32-bit systems, this truncation can bypass byte-slice limits, select incorrect union branches, or cause panics. Additionally, on all platforms, cumulative size arithmetic in array and map decoders can overflow, bypassing allocation limits or causing panics. Unsafe negation of minimum integer values and allocation with negative sizes can also cause panics. Exploitation requires only an untrusted Avro stream.

Impact Analysis

This vulnerability can lead to denial-of-service (DoS) conditions by causing panics in the Avro decoder when processing maliciously crafted data. On 32-bit systems, it can also bypass size limits and cause incorrect data processing, potentially leading to logic errors. Exploiting this vulnerability requires only supplying a malicious Avro stream, which can crash or disrupt applications using the affected decoder versions.

Detection Guidance

This vulnerability arises from processing untrusted Avro streams with affected versions of the iskorotkov/avro decoder library. Detection involves identifying usage of vulnerable library versions (prior to 2.33.0) in your environment and monitoring for abnormal decoder behavior such as panics or denial-of-service symptoms during Avro data processing.

Specific commands to detect the vulnerability are not provided in the available resources. However, you can check the version of the iskorotkov/avro library in your projects by inspecting your dependency files or using package management commands, for example:

  • For Go modules: run `go list -m all | grep github.com/iskorotkov/avro` to see the version in use.
  • Monitor application logs for panics or errors related to Avro decoding, which may indicate exploitation attempts.

Network detection of exploit attempts would require monitoring for unusual or malformed Avro data streams, but no specific network detection commands or signatures are provided.

Mitigation Strategies

The primary mitigation is to upgrade the iskorotkov/avro library to version 2.33.0 or later, where the vulnerability is fixed.

If upgrading immediately is not possible, temporary mitigations include:

  • Avoid processing untrusted Avro data streams to prevent exploitation.
  • Isolate Avro decoding workers to limit the impact of potential denial-of-service conditions.
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