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High 7.5Published Oct 7, 2026

CVE-2026-107161Cyrus-sasl: heap buffer overflow in cyrus-sasl add_to_challenge() allows malicious server to crash or compromise digest-md5 clients

Updated under an hour ago ()

Does this affect you?

It affects Red Hat Enterprise Linux 10 and 2 other products. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.28%, higher than 19% of scored CVEs.

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.

CVSS
7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-122
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
0.28% (percentile 19)
Assigned by
redhat
NVD analysis
Awaiting Analysis
Record last updated
Oct 10, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
10
CNA record
1
CNA record
4
CNA record

References

  • vdb-entry, x-refsource-redhat
  • issue-tracking, x-refsource-redhat

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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