Heap buffer overflow in Cyrus SASL DIGEST-MD5 plugin
Priority LOW 35CWE-122Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- High
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.
Summary
Cyrus SASL contains a heap-based buffer overflow (CWE-122) in the add_to_challenge() function of its DIGEST-MD5 plugin. The buffer is sized before DIGEST-MD5 quoting is applied and is not resized when quoting makes the value longer, so the code writes past the end of the heap buffer. A malicious or on-path DIGEST-MD5 or HTTP Digest server can trigger this in a connecting client by supplying a crafted challenge field such as nonce, most likely crashing the client.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00376 31st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 6 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 7 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Hardened Images | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift AI (RHOAI) | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — | Not affected | CNA |
- Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Enterprise Linux 6 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Enterprise Linux 7 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift AI (RHOAI) VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift Container Platform 5 VendorRed Hat Affected — Fixed in — Not affected CNA
CPE names CNA · 9
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:/a:redhat:enterprise_linux:10 | 10 | — | Red Hat |
| cpe:/o:redhat:rhel_els:6 | 6 | — | Red Hat |
| cpe:/o:redhat:rhel_els:7 | 7 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:8 | 8 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:9 | 9 | — | Red Hat |
| cpe:/a:redhat:hummingbird:1 | 1 | — | Red Hat |
| cpe:/a:redhat:openshift_ai | — | — | Red Hat |
| cpe:/a:redhat:openshift:4 | 4 | — | Red Hat |
| cpe:/a:redhat:openshift:5 | 5 | — | Red Hat |
- cpe:/a:redhat:enterprise_linux:10 Versions 10 — ·Red Hat
- cpe:/o:redhat:rhel_els:6 Versions 6 — ·Red Hat
- cpe:/o:redhat:rhel_els:7 Versions 7 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:8 Versions 8 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:9 Versions 9 — ·Red Hat
- cpe:/a:redhat:hummingbird:1 Versions 1 — ·Red Hat
- cpe:/a:redhat:openshift_ai Versions — — ·Red Hat
- cpe:/a:redhat:openshift:4 Versions 4 — ·Red Hat
- cpe:/a:redhat:openshift:5 Versions 5 — ·Red Hat
Remediation
The sources list no fixed version for Red Hat Enterprise Linux 6, 7, 8, 9 and 10, Red Hat Hardened Images and Red Hat OpenShift AI (RHOAI). Red Hat's plan is no fix planned for Red Hat Enterprise Linux 6 and none available for the other listed products.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat Hardened Images | Affected | No fix yet |
| Red Hat OpenShift AI (RHOAI) | Affected | — |
Not affected: 3 products
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-07 Threatist record created from CVE-2026-107161
- 2026-10-07 Alias added: GHSA-4jhc-cc62-fwcm
- 2026-10-08 Affected versions changed · Red Hat
- 2026-10-08 CVSS score added · Red Hat
- 2026-10-09 Affected versions changed · Red Hat
- 2026-10-09 Priority changed: MEDIUM → LOW
- 2026-10-09 Affected versions changed · CNA
- 2026-10-10 CISA SSVC decision points changed
- 2026-10-30 Affected versions changed · CNA
- 2026-10-31 Affected versions changed · Red Hat
- 2026-11-06 Affected versions changed · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
More Red Hat vulnerabilities
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- TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
- TI-2019-05363 Code injection in Elastic Kibana KEVCVSS 3.1CRITICAL 10.0
- TI-2019-03949 Out-of-bounds write in ESXi and Horizon DaaS KEVCVSS 3.1CRITICAL 9.8
- TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-107161 · CVE Program
- CVE-2026-107161 · NVD
- FIRST EPSS
- GHSA-4jhc-cc62-fwcm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-107161 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences