CVE-2020-15572

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-07-15 · updated 2026-06-17
Weakness: CWE-125

Description

Tor before 0.4.3.6 has an out-of-bounds memory access that allows a remote denial-of-service (crash) attack against Tor instances built to use Mozilla Network Security Services (NSS), aka TROVE-2020-001.

Affected products

torproject Tor: before 0.3.5.11; from 0.4.2.0 (excl.) before 0.4.2.8; from 0.4.3.0 (excl.) before 0.4.3.6; 0.4.4.0-alpha, 0.4.4.1-alpha — fixed in 0.3.5.11, 0.4.2.8, 0.4.3.6

How to fix

Upgrade to a fixed version: torproject Tor 0.3.5.11, 0.4.2.8, 0.4.3.6. Check the vendor advisory for mitigations.

References

https://blog.torproject.org/new-release-tor-03511-0428-0436-security-fixes
https://gitlab.torproject.org/tpo/core/tor/-/issues/33119
https://trac.torproject.org/projects/tor/wiki/TROVE
https://blog.torproject.org/new-release-tor-03511-0428-0436-security-fixes
https://gitlab.torproject.org/tpo/core/tor/-/issues/33119
https://trac.torproject.org/projects/tor/wiki/TROVE

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