Out-of-bounds Read in Opensmtpd
CVE-2020-8794
OpenSMTPD before 6.6.4 allows remote code execution because of an out-of-bounds read in mta_io in mta_session.c for multi-line replies. Although this vulnerability affects the client side of OpenSMTPD, it is possible to attack a server because the server code launches the client code during bounce handling.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.889 (99.8th percentile), scored .
High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.889 · newest: 0.889 · change: 0.000
Affected products
- Opensmtpd
- Canonical Ubuntu Linux — versions 18.04, 19.10
- Debian Linux — versions 9.0, 10.0
- Fedoraproject Fedora — versions 31, 32
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.openbsd.org/security.html (Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/02/24/5 (Exploit, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/02/26/1 (mailing-list, Exploit, Mailing List, Third Party Advisory)
- www.debian.org/security/2020/dsa-4634 (vendor-advisory, Third Party Advisory)
- seclists.org/fulldisclosure/2020/Feb/32 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/03/01/1 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/03/01/2 (mailing-list, Mailing List, Third Party Advisory)
- packetstormsecurity.com/files/156633/OpenSMTPD-Out-Of-Bounds-Read-Local-Privile… (Exploit, VDB Entry, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- usn.ubuntu.com/4294-1/ (vendor-advisory, Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-8794?
- CVE-2020-8794 is a critical-severity vulnerability in Opensmtpd, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2020-02-25.
- How severe is CVE-2020-8794?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2020-8794 known to be exploited?
- 24 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.