CVE-2026-107161
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.
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat Red Hat Enterprise Linux 10 | No range specified | — |
| Red Hat Red Hat Enterprise Linux 7 | No range specified | — |
| Red Hat Red Hat Enterprise Linux 8 | No range specified | — |
| Red Hat Red Hat Enterprise Linux 9 | No range specified | — |
| Red Hat Red Hat Hardened Images | No range specified | — |
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