Denial of Service in TenderMint

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2020-15091: 0.91% estimated exploitation activity in the next 30 days; percentile 59.86 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description Denial of Service Tendermint 0.33.0 and above allow block proposers to include signatures for the wrong block. This may happen naturally if you start a network, have it run for some time and restart it without changing the chainID. (It is a misconfiguration to reuse chainIDs.) Correct block proposers will accidentally include signatures for the wrong block if they see these signatures, and then commits won't validate, making all proposed blocks invalid. A malicious validator (even with a minimal amount of stake) can use this vulnerability to completely halt the network. Tendermint 0.33.6 checks all the signatures are for the block with +2/3 majority before creating a commit. False Witness Tendermint 0.33.1 and above are no longer fully verifying commit signatures during block execution - they stop after +2/3. This means proposers can propose blocks that contain valid +2/3 signatures and then the rest of the signatures can be whatever they want. They can claim that all the…

Published by the source

20 Dec 2021, 18:17 UTC

Last modified by the source

31 May 2024, 17:46 UTC

Source last checked

26 Oct 2026, 15:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6jqj-f58p-mrw3

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# Patch Next advisory brief: CVE-2020-15091

Advisory: Denial of Service in TenderMint
IDs: CVE-2020-15091, GHSA-6jqj-f58p-mrw3
Record: https://patchnext.com/advisories/cve-2020-15091 (revision 1, source checked 26 Oct 2026, 15:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/tendermint/tendermint 0.33.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/tendermint/tendermint: affected < 0.33.6; fixed in 0.33.6

## Suggested inspection (read-only)
- Go github.com/tendermint/tendermint: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/tendermint/tendermint.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6jqj-f58p-mrw3 (GitHub-reviewed advisory GHSA-6jqj-f58p-mrw3 lists affected ranges: Go github.com/tendermint/tendermint >=0 <0.33.6)

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