In Apache SpamAssassin before 3.4.3, a message can be crafted in a way to use excessive resources. Upgrading to SA 3.4.3 as soon as possible is the recommended fix but details will not be shared publicly.
https://www.debian.org/security/2019/dsa-4584
https://usn.ubuntu.com/4237-2/
https://usn.ubuntu.com/4237-1/
https://seclists.org/bugtraq/2019/Dec/27
https://lists.debian.org/debian-lts-announce/2019/12/msg00019.html
http://www.openwall.com/lists/oss-security/2019/12/12/2
https://svn.apache.org/repos/asf/spamassassin/branches/3.4/build/announcements/3.4.3.txt
https://lists.apache.org/thread.html/r3d32ebf97b1245b8237763444e911c4595d2ad5e34a1641840d8146f%40%3Cusers.spamassassin.apache.org%3E
https://lists.apache.org/thread.html/r2578c486552637bfedbe624940cc60d6463bd90044c887bdebb75e74%40%3Cusers.spamassassin.apache.org%3E
https://lists.apache.org/thread.html/e3c2367351286b77a74a082e2b66b793cceefa7b6ea9dcd162db4c4b%40%3Cdev.spamassassin.apache.org%3E
https://lists.apache.org/thread.html/64cf76749956dd08f7d5b86ec9f3321f382cfd7fe717ccd1be940c92%40%3Cannounce.spamassassin.apache.org%3E
https://lists.apache.org/thread.html/5ef362d6da12126fafc81443309ca95d872d1bfd011fe4b2699f0fe9%40%3Cusers.spamassassin.apache.org%3E
https://lists.apache.org/thread.html/5863d6c42fc9595a29566732f12348cde0ca0e41bda91695c62041de%40%3Cannounce.apache.org%3E
https://bz.apache.org/SpamAssassin/show_bug.cgi?id=7747
Source: Mitre, NVD
Published: 2019-12-12
Updated: 2023-11-07
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: High
EPSS: 0.17694