CVE-2020-5303
Denial of service in Tendermint
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Tendermint before versions 0.33.3, 0.32.10, and 0.31.12 has a denial-of-service vulnerability. Tendermint does not limit the number of P2P connection requests. For each p2p connection, it allocates XXX bytes. Even though this memory is garbage collected once the connection is terminated (due to duplicate IP or reaching a maximum number of inbound peers), temporary memory spikes can lead to OOM (Out-Of-Memory) exceptions. Additionally, Tendermint does not reclaim activeID of a peer after it's removed in Mempool reactor. This does not happen all the time. It only happens when a connection fails (for any reason) before the Peer is created and added to all reactors. RemovePeer is therefore called before AddPeer, which leads to always growing memory (activeIDs map). The activeIDs map has a maximum size of 65535 and the node will panic if this map reaches the maximum. An attacker can create a lot of connection attempts (exploiting above denial of service), which ultimately will lead to the node panicking. These issues are patched in Tendermint 0.33.3 and 0.32.10.
Timeline
ID reserved
By GitHub_M
- 3 months later
· 3 months later
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Low3.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L |
| NVDNVD · Modified | 3.1 | Low3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L |
- EPSS (exploitation in 30 days)
- 1.4% · top 28% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.1.
Weakness
Affected products
- affected >= 0.32.0, < 0.32.10
- affected >= 0.33.0, < 0.33.3
- affected < 0.31.12
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/tendermint/tendermintGHSA-v24h-pjjv-mcp6 (opens in a new tab)
References (3)
- https://github.com/tendermint/tendermint/security/advisories/GHSA-v24h-pjjv-mcp6 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://hackerone.com/reports/820317 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/tendermint/tendermint/commit/e2d6859afd7dba4cf97c7f7d412e7d8fc908d1cd (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-v24h-pjjv-mcp6 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2020-5303)Record last updated .