Red Hat Security Advisory: krb5 security update
Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC). Security Fix(es): * krb5: MIT Kerberos 5 (krb5): Denial of Service via integer underflow and out-of-bounds read (CVE-2026-40356) * krb5: MIT Kerberos 5: Denial of Service via NULL pointer dereference in NegoEx mechanism (CVE-2026-40355) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
AI Analysis
Technical Summary
MIT Kerberos 5, a network authentication protocol implementation, contains multiple vulnerabilities that can cause denial of service. Specifically, CVE-2026-40356 involves an integer underflow and out-of-bounds read, while CVE-2026-40355 involves a NULL pointer dereference in the NegoEx mechanism. These flaws can be triggered to crash or disrupt the Kerberos service. Red Hat has issued security advisories and updates for affected packages in Red Hat Enterprise Linux 8 and hardened images to remediate these issues.
Potential Impact
Successful exploitation of these vulnerabilities results in denial of service conditions, potentially disrupting authentication services that rely on MIT Kerberos 5. This can affect network security and availability but does not indicate remote code execution or data compromise based on the provided data.
Mitigation Recommendations
Red Hat has released official security updates that fix these vulnerabilities in MIT Kerberos 5 packages for Red Hat Enterprise Linux 8 and hardened images. Users should apply these updates promptly. For detailed update instructions, refer to the Red Hat advisories at https://access.redhat.com/errata/RHSA-2026:12220 and https://access.redhat.com/errata/RHSA-2026:16799. No additional mitigation is indicated by the vendor advisory.
Red Hat Security Advisory: krb5 security update
Description
Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC). Security Fix(es): * krb5: MIT Kerberos 5 (krb5): Denial of Service via integer underflow and out-of-bounds read (CVE-2026-40356) * krb5: MIT Kerberos 5: Denial of Service via NULL pointer dereference in NegoEx mechanism (CVE-2026-40355) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
MIT Kerberos 5, a network authentication protocol implementation, contains multiple vulnerabilities that can cause denial of service. Specifically, CVE-2026-40356 involves an integer underflow and out-of-bounds read, while CVE-2026-40355 involves a NULL pointer dereference in the NegoEx mechanism. These flaws can be triggered to crash or disrupt the Kerberos service. Red Hat has issued security advisories and updates for affected packages in Red Hat Enterprise Linux 8 and hardened images to remediate these issues.
Potential Impact
Successful exploitation of these vulnerabilities results in denial of service conditions, potentially disrupting authentication services that rely on MIT Kerberos 5. This can affect network security and availability but does not indicate remote code execution or data compromise based on the provided data.
Mitigation Recommendations
Red Hat has released official security updates that fix these vulnerabilities in MIT Kerberos 5 packages for Red Hat Enterprise Linux 8 and hardened images. Users should apply these updates promptly. For detailed update instructions, refer to the Red Hat advisories at https://access.redhat.com/errata/RHSA-2026:12220 and https://access.redhat.com/errata/RHSA-2026:16799. No additional mitigation is indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:19357
- Cve Count
- 2
- Additional Cves
- ["CVE-2026-40356"]
- State
- PUBLISHED
Threat ID: 6a175eeee29bf47b50edca44
Added to database: 05/27/2026, 21:15:26 UTC
Last enriched: 07/03/2026, 01:17:20 UTC
Last updated: 09/14/2026, 10:01:30 UTC
Views: 117
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