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Fencer Vulns
high 7.5

CVE-2026-107161 json

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

published 2026-10-07 32 d ago modified 2026-11-06 2 d ago also EUVD-2026-94582

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • cyrus-sasl2 Debian 12 2.1.28+dfsg-10+deb12u1
  • cyrus-sasl2 Debian 14 2.1.28+dfsg1-12

debian advisories DEBIAN-CVE-2026-107161

  • cyrus-sasl Linux Micro 6.1 2.1.28-slfo.1.1_2.1
  • cyrus-sasl SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 2.1.28-150600.7.17.1
  • cyrus-sasl-bdb SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Server Applications 15 SP7 +1 more 2.1.28-150600.7.17.1
  • cyrus-sasl-saslauthd SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Server Applications 15 SP7 +1 more 2.1.28-150600.7.17.1
  • cyrus-sasl-saslauthd-bdb SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Legacy 15 SP7 2.1.28-150600.7.17.1
  • cyrus-sasl SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 2.1.28-150500.3.12.1
  • cyrus-sasl-bdb SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 2.1.28-150500.3.12.1
  • cyrus-sasl-saslauthd SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 2.1.28-150500.3.12.1

suse advisories SUSE-SU-2026:24380-1SUSE-SU-2026:4836-1SUSE-SU-2026:4817-1SUSE-SU-2026:4802-1SUSE-SU-2026:4795-1SUSE-SU-2026:24266-1

  • cyrus-sasl openSUSE Leap 16.0 2.1.28-160000.4.1
  • cyrus-sasl-bdb openSUSE Leap 16.0 2.1.28-160000.4.1
  • cyrus-sasl-saslauthd openSUSE Leap 16.0 2.1.28-160000.4.1
  • cyrus-sasl-saslauthd-bdb openSUSE Leap 16.0 2.1.28-160000.4.1
  • cyrus-sasl openSUSE Tumbleweed 2.1.28-13.1

opensuse advisories openSUSE-SU-2026:22146-1openSUSE-SU-2026:12099-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-107161 updated cvss 7.5

cyrus-sasl: Heap buffer overflow in cyrus-sasl add_to_challenge() allows malicious server to crash or compromise DIGEST-MD5 clients

  • Red Hat Enterprise Linux 6 cyrus-sasl, cyrus-sasl-lib, cyrus-sasl-md5, cyrus-sasl-sql, cyrus-sasl-ldap, cyrus-sasl-ntlm, +2 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 cyrus-sasl, cyrus-sasl-gs2, cyrus-sasl-lib, cyrus-sasl-md5, cyrus-sasl-sql, cyrus-sasl-ldap, +4 more Red Hat Enterprise Linux 8 cyrus-sasl, cyrus-sasl-gs2, cyrus-sasl-lib, cyrus-sasl-md5, cyrus-sasl-sql, cyrus-sasl-ldap, +4 more Red Hat Enterprise Linux 9 cyrus-sasl, cyrus-sasl-gs2, cyrus-sasl-lib, cyrus-sasl-md5, cyrus-sasl-sql, cyrus-sasl-ldap, +4 more Red Hat Enterprise Linux 10 cyrus-sasl Red Hat Hardened Images cyrus-sasl
    affected: workaround, no fix available
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more
    under investigation
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-ogx-k8s-operator-rhel9, +14 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
30 d ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat OpenShift AI (RHOAI)
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 5

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.