CVE-2020-5303Network attack vector

Node crash via unbounded P2P connections

Published Apr 10, 2020 · Updated Aug 4, 2024

Denial of service in Tendermint Core 0.33.2 and earlier allows remote attackers to crash full nodes through repeated P2P connections. The P2P transport accepts unlimited incoming requests, while the Mempool reactor can also fail to reclaim an activeID when a connection fails before peer initialization, causing transient or persistent memory growth. Internet- or intranet-reachable full nodes can panic after the activeIDs map fills or terminate from memory exhaustion; validators isolated behind closed networks are not exposed.

CVSS severity3.7
Low
EPSS probability1.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Tendermint Core 0.33.2 and earlier allows remote attackers to crash full nodes through repeated P2P connections. The P2P transport accepts unlimited incoming requests, while the Mempool reactor can also fail to reclaim an activeID when a connection fails before peer initialization, causing transient or persistent memory growth. Internet- or intranet-reachable full nodes can panic after the activeIDs map fills or terminate from memory exhaustion; validators isolated behind closed networks are not exposed.

The record

CVE
CVE-2020-5303
Published
Apr 10, 2020
Updated
Aug 4, 2024
Vendor
Tendermint
Product
Tendermint Core
Classifications
CWE-789, CWE-787, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 10, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.31.12
  2. Affected versionversion=>= 0.32.0, < 0.32.10
  3. Affected versionversion=>= 0.33.0, < 0.33.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tendermint · Tendermint Coreversion=< 0.31.12; version=>= 0.32.0, < 0.32.10; version=>= 0.33.0, < 0.33.3

Published CVSS scores

3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
3.1GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-789Uncontrolled Memory Allocation
CWE-787Out-of-bounds Write
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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