# CVE-2026-46384: iskorotkov/avro: Integer Overflow in Avro Decoder

> An integer overflow in the Avro decoder allows attackers to cause denial of service via crafted wire data, affecting Go applications using this library.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 May 2026
- **Updated:** 9 Sep 2026
- **Also known as:** CLEANSTART-2026-OC65690, CLEANSTART-2026-TF86482, GHSA-mc57-h6j3-3hmv, GO-2026-5047, MINI-2x53-3q4m-x99j, MINI-3229-xjxx-pp3w, MINI-3rw7-74xx-9hmm, MINI-45pr-jqg9-mjvx, MINI-53fh-cmcc-cm9f, MINI-62fr-w37f-4jj6, MINI-65j5-v85m-2x98, MINI-9c88-jg46-wmmv, MINI-gmpr-gqwm-6fxj, MINI-gpgf-mcj5-3rhc, MINI-jc23-pv9j-c42c, MINI-rmx6-6vh5-v2qq, MINI-v53m-hg8j-mgfm, MINI-vc54-74rh-gwxp, MINI-vm56-m86q-wvg2, ROOT-APP-GOBINARY-CVE-2026-46384

## What is CVE-2026-46384?

CVE-2026-46384 is a high-severity vulnerability in iskorotkov avro, published on 29 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-46384?

4 open source packages ship an affected version, including github.com/iskorotkov/avro/v2 and github.com/hamba/avro/v2.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/iskorotkov/avro/v2` | Go | All versions | 2.33.0 |
| `github.com/iskorotkov/avro/v2` | Go | All versions | 2.33.0 |
| `github.com/iskorotkov/avro/v2` | Go | All versions | 2.33.0 |
| `github.com/hamba/avro/v2` | Go | All versions | None |

## How do I fix CVE-2026-46384?

Upgrade github.com/iskorotkov/avro/v2 to 2.33.0 or later.

## Is CVE-2026-46384 being exploited?

There is no known exploitation of CVE-2026-46384 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46384 and fix it if it is affected.

What it is: CVE-2026-46384 is a high-severity vulnerability in iskorotkov avro, published on 29 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-46384 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/iskorotkov/avro/v2 (Go): affected all versions; fixed in 2.33.0
- github.com/iskorotkov/avro/v2 (Go): affected all versions; fixed in 2.33.0
- github.com/iskorotkov/avro/v2 (Go): affected all versions; fixed in 2.33.0
- github.com/hamba/avro/v2 (Go): affected all versions; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-46384/ (Markdown: https://insights.sbomify.com/CVE-2026-46384/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46384
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46384
- OSV: https://osv.dev/vulnerability/CVE-2026-46384

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46384/
Summaries are generated and may contain mistakes; the official description above is the record.