# CVE-2026-82409: Klever-Go: Elasticsearch bulk / painless injection via on-chain account name -> explorer/indexer data forgery

> Attackers can inject malicious JSON into Elasticsearch bulk requests via account names, allowing data forgery or service disruption in the Klever-Go indexer.

- **Severity:** High 8.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-7c7c-373r-gfjj, GO-2026-6585

## What is CVE-2026-82409?

CVE-2026-82409 is a high-severity code injection vulnerability in klever-io klever-go, published on 23 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, indexer/common.go serializedDataForUpdateAccounts places the attacker-controlled acc.Name value into an Elasticsearch _bulk JSON and NDJSON request without escaping it. The SetAccountName transaction accepts valid UTF-8 account names containing quotes, backslashes, and newlines, and the resulting name is stored in consensus account state. When an indexer processes the account, those characters can break the JSON string, reject a bulk batch, or inject additional bulk actions that create, overwrite, or delete documents in indices writable by the indexer. The persistent state value is replayed by new or historical indexers, and direct access to the indexing host or Elasticsearch port is not required. This issue is fixed in version 1.7.20.

Weakness: CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-82409?

3 open source packages ship an affected version, including github.com/klever-io/klever-go.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/klever-io/klever-go` | Go | All versions | 1.7.20 |
| `github.com/klever-io/klever-go` | Go | All versions | 1.7.20 |
| `github.com/klever-io/klever-go` | Go | All versions | 1.7.20 |

## How do I fix CVE-2026-82409?

Upgrade github.com/klever-io/klever-go to 1.7.20 or later.

## Is CVE-2026-82409 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82409 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82409 and fix it if it is affected.

What it is: CVE-2026-82409 is a high-severity code injection vulnerability in klever-io klever-go, published on 23 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82409 exists.

Affected packages and fixed versions:
- github.com/klever-io/klever-go (Go): affected all versions; fixed in 1.7.20
- github.com/klever-io/klever-go (Go): affected all versions; fixed in 1.7.20
- github.com/klever-io/klever-go (Go): affected all versions; fixed in 1.7.20

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-2026-82409/ (Markdown: https://insights.sbomify.com/CVE-2026-82409/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82409
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82409
- OSV: https://osv.dev/vulnerability/CVE-2026-82409

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82409/
Summaries are generated and may contain mistakes; the official description above is the record.