A heap-based buffer overflow flaw was found in Cyrus SASL. The add_to_challenge() function in the DIGEST-MD5 plugin computes the size of the buffer needed for a challenge/response field before DIGEST-MD5 quoting is applied, but does not recompute that size when quoting (escaping special characters) makes the value longer. The under-sized buffer is then passed to strcat(), causing a heap-based out-of-bounds write whose size depends on attacker-controlled input. A malicious or on-path DIGEST-MD5 (or HTTP Digest) server can trigger this flaw in a connecting client by supplying a crafted challenge field, such as realm or nonce, most likely resulting in a crash of the client application.
History

Sat, 10 Oct 2026 03:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 09 Oct 2026 23:30:00 +0000

Type Values Removed Values Added
References

Fri, 09 Oct 2026 09:15:00 +0000

Type Values Removed Values Added
First Time appeared Cyrusimap
Cyrusimap cyrus-sasl
Redhat hardened Images
Redhat openshift Container Platform
Vendors & Products Cyrusimap
Cyrusimap cyrus-sasl
Redhat hardened Images
Redhat openshift Container Platform

Thu, 08 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 07 Oct 2026 19:45:00 +0000

Type Values Removed Values Added
Description A heap-based buffer overflow flaw was found in Cyrus SASL. The add_to_challenge() function in the DIGEST-MD5 plugin computes the size of the buffer needed for a challenge/response field before DIGEST-MD5 quoting is applied, but does not recompute that size when quoting (escaping special characters) makes the value longer. The under-sized buffer is then passed to strcat(), causing a heap-based out-of-bounds write whose size depends on attacker-controlled input. A malicious or on-path DIGEST-MD5 (or HTTP Digest) server can trigger this flaw in a connecting client by supplying a crafted challenge field, such as realm or nonce, most likely resulting in a crash of the client application.
Title Cyrus-sasl: heap buffer overflow in cyrus-sasl add_to_challenge() allows malicious server to crash or compromise digest-md5 clients
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-122
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published: 2026-10-07T19:29:28.164Z

Updated: 2026-10-10T02:42:51.112Z

Reserved: 2026-10-07T11:00:41.139Z

Link: CVE-2026-107161

cve-icon Vulnrichment

Updated: 2026-10-09T22:07:16.666Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-07T20:17:10.977

Modified: 2026-10-10T03:17:05.307

Link: CVE-2026-107161

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-07T17:53:01Z

Links: CVE-2026-107161 - Bugzilla