An issue was discovered in Malwarebytes before 4.0 on macOS.

published 2021-01-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-18218

cvss: 7.0; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

An issue was discovered in Malwarebytes before 4.0 on macOS. A malicious application was able to perform a privileged action within the Malwarebytes launch daemon. The privileged service improperly validated XPC connections by relying on the PID instead of the audit token. An attacker can construct a situation where the same PID is used for running two different programs at different times, by leveraging a race condition during crafted use of posix_spawn.

Patch / fix

fixed in 1 links 1

malwarebytes malwarebytes 4.0

wojciechregula.blog/post/learn-xpc-exploitation-part-2-say-no-to-the-pid/ advisory

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

wojciechregula.blog https://wojciechregula.blog/post/learn-xpc-exploitation-part-2-say-no-to-the-pid/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.9	AV:L/AC:M/Au:N/C:C/I:C/A:C

Classification

Weakness

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

wojciechregula.blog /post/learn-xpc-exploitation-part-2-say-no-to-the-pid/
exploit, patch, third-party-advisory

Sources

CVE List CVE-2020-25533
NVD CVE-2020-25533

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary