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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-107161

Cyrus-sasl: heap buffer overflow in cyrus-sasl add_to_challenge() allows malicious server to crash or compromise digest-md5 clients

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Red Hat Red Hat Enterprise Linux 10

Default version status: affected

Red Hat Red Hat Enterprise Linux 6

Default version status: unknown

Red Hat Red Hat Enterprise Linux 7

Default version status: affected

Red Hat Red Hat Enterprise Linux 8

Default version status: affected

Red Hat Red Hat Enterprise Linux 9

Default version status: affected

Red Hat Red Hat Hardened Images

Default version status: affected

Red Hat Red Hat OpenShift Container Platform 4

Default version status: unaffected

Red Hat Red Hat OpenShift Container Platform 4

Default version status: unaffected

References