Bug 1268793 (CVE-2015-7687)

Summary: CVE-2015-7687 OpenSMTPD: multiple vulnerabilities fixed in 5.7.2
Product: [Other] Security Response Reporter: Martin Prpič <mprpic>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: carnil, denis, jrusnack
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: OpenSMTPD 5.7.2 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-10-26 19:11:21 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1268794, 1268795    
Bug Blocks:    

Description Martin Prpič 2015-10-05 09:19:11 UTC
Several vulnerabilities have been fixed in OpenSMTPD 5.7.2:

- an oversight in the portable version of fgetln() that allows attackers to read and write out-of-bounds memory;

- multiple denial-of-service vulnerabilities that allow local users to kill or hang OpenSMTPD;

- a stack-based buffer overflow that allows local users to crash OpenSMTPD, or execute arbitrary code as the non-chrooted _smtpd user;

- a hardlink attack (or race-conditioned symlink attack) that allows local users to unset the chflags() of arbitrary files;

- a hardlink attack that allows local users to read the first line of arbitrary files (for example, root's hash from /etc/master.passwd);

- a denial-of-service vulnerability that allows remote attackers to fill OpenSMTPD's queue or mailbox hard-disk partition;

- an out-of-bounds memory read that allows remote attackers to crash OpenSMTPD, or leak information and defeat the ASLR protection;

- a use-after-free vulnerability that allows remote attackers to crash OpenSMTPD, or execute arbitrary code as the non-chrooted _smtpd user;

Further details can be found in Qualys' audit report:


MITRE has assigned one CVE for the use-after-free vulnerability; additional CVEs may be assigned:


External References:


Comment 1 Martin Prpič 2015-10-05 09:19:43 UTC
Created opensmtpd tracking bugs for this issue:

Affects: fedora-all [bug 1268794]
Affects: epel-all [bug 1268795]

Comment 2 Denis Fateyev 2015-10-05 11:38:19 UTC
This update is already in testing. Just edited the descriptions on Bodhi to be more specific on vulnerabilities fixed, and added bugs above.

Everybody interested is encouraged to test the update and give feedback.

Comment 3 Denis Fateyev 2015-10-26 19:11:21 UTC
Fixed in opensmtpd version 5.7.3 which is on stable.