CVE-2020-5303

Denial of service in Tendermint

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.

Categories

3.1
CVSS
Severity: Low
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.32%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory hackerone.com
Affected: Tendermint Tendermint
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2020-5303?
CVE-2020-5303 has been scored as a low severity vulnerability.
How to fix CVE-2020-5303?
To fix CVE-2020-5303, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-5303 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2020-5303 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-5303?
CVE-2020-5303 affects Tendermint Tendermint.
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