Use After Free in Exim

CVE-2017-16943

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.

Vulnerability class: Use-After-Free

EPSS: 0.745 (98.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2017-16943?
CVE-2017-16943 is a critical-severity vulnerability in Exim, classified under Use After Free. CVSS score: 9.8/10. Published 2017-11-25.
How severe is CVE-2017-16943?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2017-16943 known to be exploited?
10 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.