# CVE-2026-52878: Klever-Go: Unauthenticated nil-pointer DoS in P2P transaction validation can halt the chain

> An unauthenticated attacker can crash Klever-Go nodes and halt the blockchain by sending a malformed P2P transaction that triggers a nil-pointer panic.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Aug 2026
- **Updated:** 10 Aug 2026
- **Also known as:** GHSA-rm5c-5x2p-48wr, GO-2026-5628

## What is CVE-2026-52878?

CVE-2026-52878 is a high-severity vulnerability in klever-io klever-go, published on 7 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Klever-Go is the Go implementation of the Klever blockchain protocol. Versions 1.7.14 through 1.7.17 are vulnerable to a nil-pointer panic triggered by a protobuf Transaction whose embedded RawData sub-message is omitted. This omission causes RawData to decode to nil. Every transaction gossiped on the Klever-Go P2P network is decoded and validated synchronously inside the libp2p pubsub topic-validator callback, where txVersionChecker.CheckTxVersion dereferences tx.RawData.Version with no nil check. Because the libp2p pubsub callback, the underlying go-libp2p-pubsub validation worker, and Klever's own network/p2p layer install no recover(), the panic propagates and crashes the entire node process. The attacker payload is a 3-byte protobuf message; no validator key, stake, funds, or on-chain account is required, and delivery aimed at enough of the BLS validator set can halt block production, resulting in a chain halt. This issue has been fixed in version 1.7.18.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-52878?

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 | From 1.7.14 | 1.7.18 |
| `github.com/klever-io/klever-go` | Go | From 1.7.14 | 1.7.18 |
| `github.com/klever-io/klever-go` | Go | From 1.7.14 | 1.7.18 |

## How do I fix CVE-2026-52878?

Upgrade github.com/klever-io/klever-go to 1.7.18 or later.

## Is CVE-2026-52878 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52878 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52878 and fix it if it is affected.

What it is: CVE-2026-52878 is a high-severity vulnerability in klever-io klever-go, published on 7 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52878 exists.

Affected packages and fixed versions:
- github.com/klever-io/klever-go (Go): affected from 1.7.14; fixed in 1.7.18
- github.com/klever-io/klever-go (Go): affected from 1.7.14; fixed in 1.7.18
- github.com/klever-io/klever-go (Go): affected from 1.7.14; fixed in 1.7.18

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-2026-52878/ (Markdown: https://insights.sbomify.com/CVE-2026-52878/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52878
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52878
- OSV: https://osv.dev/vulnerability/CVE-2026-52878

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52878/
Summaries are generated and may contain mistakes; the official description above is the record.