# CVE-2023-34451: CometBFT may duplicate transactions in the mempool's data structures > Attackers can duplicate transactions in the mempool to exhaust memory and crash nodes, requiring an upgrade to fix. - **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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:** 3 Jul 2023 - **Updated:** 22 Nov 2024 - **Also known as:** GHSA-w24w-wp77-qffm, GO-2023-1883 ## What is CVE-2023-34451? CVE-2023-34451 is a high-severity denial of service vulnerability in cometbft, published on 3 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description CometBFT is a Byzantine Fault Tolerant (BFT) middleware that takes a state transition machine and replicates it on many machines. The mempool maintains two data structures to keep track of outstanding transactions: a list and a map. These two data structures are supposed to be in sync all the time in the sense that the map tracks the index (if any) of the transaction in the list. In `v0.37.0`, and `v0.37.1`, as well as in `v0.34.28`, and all previous releases of the CometBFT repo2, it is possible to have them out of sync. When this happens, the list may contain several copies of the same transaction. Because the map tracks a single index, it is then no longer possible to remove all the copies of the transaction from the list. This happens even if the duplicated transaction is later committed in a block. The only way to remove the transaction is by restarting the node. The above problem can be repeated on and on until a sizable number of transactions are stuck in the mempool, in order to try to bring down the target node. The problem is fixed in releases `v0.34.29` and `v0.37.2`. Some workarounds are available. Increasing the value of `cache_size` in `config.toml` makes it very difficult to effectively attack a full node. Not exposing the transaction submission RPC's would mitigate the probability of a successful attack, as the attacker would then have to create a modified (byzantine) full node to be able to perform the attack via p2p. Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime) ## Which versions are affected by CVE-2023-34451? 5 open source packages ship an affected version, including github.com/cometbft/cometbft. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/cometbft/cometbft` | Go | All versions | 0.34.29 | | `github.com/cometbft/cometbft` | Go | All versions | 0.34.29 | | `github.com/cometbft/cometbft` | Go | All versions | 0.37.2 | | `github.com/cometbft/cometbft` | Go | From 0.37.0 | 0.37.2 | | `github.com/cometbft/cometbft` | Go | From 0.37.0 | 0.37.2 | Products: Cometbft Cometbft. ## How do I fix CVE-2023-34451? Upgrade github.com/cometbft/cometbft to a fixed version for your release line: 0.34.29 or 0.37.2. ## Is CVE-2023-34451 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-34451 exists. ## Other vulnerabilities in cometbft - [CVE-2023-34450](https://insights.sbomify.com/CVE-2023-34450/): CometBFT PeerState JSON serialization deadlock (low 3.7) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-34451 and fix it if it is affected. What it is: CVE-2023-34451 is a high-severity denial of service vulnerability in cometbft, published on 3 Jul 2023. 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-2023-34451 exists. Affected packages and fixed versions: - github.com/cometbft/cometbft (Go): affected all versions; fixed in 0.34.29 - github.com/cometbft/cometbft (Go): affected all versions; fixed in 0.34.29 - github.com/cometbft/cometbft (Go): affected all versions; fixed in 0.37.2 - github.com/cometbft/cometbft (Go): affected from 0.37.0; fixed in 0.37.2 - github.com/cometbft/cometbft (Go): affected from 0.37.0; fixed in 0.37.2 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-2023-34451/ (Markdown: https://insights.sbomify.com/CVE-2023-34451/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-34451 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-34451 - OSV: https://osv.dev/vulnerability/CVE-2023-34451 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-34451/ Summaries are generated and may contain mistakes; the official description above is the record.