August 27, 2026 — Small Business Cyber Watch
Today’s priority: Review the newest entries in CISA’s authoritative catalog of vulnerabilities known to be exploited in the wild. The most recent catalog additions shown below are dated August 26, 2026.
Ajax.NET Professional Ajax.NET Professional: Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
CVE-2021-23758 · Added by CISA August 26, 2026
What changed: Ajax.NET Professional (AjaxPro) contains a deserialization of untrusted data vulnerability that could allow for remote code execution via arbitrary .NET classes. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.
Why it matters: CISA includes vulnerabilities in this catalog when there is evidence they are being actively exploited. An affected internet-facing or business-critical system deserves prompt attention.
What to do: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA remediation target: September 9, 2026.
Red Hat Libuser: Red Hat Libuser Race Condition Vulnerability
CVE-2015-3246 · Added by CISA August 26, 2026
What changed: Red Hat libuser contains a race condition vulnerability that allows authenticated local users to corrupt the /etc/passwd file to cause a denial of service or privilege escalation.
Why it matters: CISA includes vulnerabilities in this catalog when there is evidence they are being actively exploited. An affected internet-facing or business-critical system deserves prompt attention.
What to do: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA remediation target: September 9, 2026.
Red Hat Automatic Bug Reporting Tool: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability
CVE-2015-5287 · Added by CISA August 26, 2026
What changed: Red Hat Automatic Bug Reporting Tool (ABRT) contains a privilege escalation vulnerability that could allow local users with certain permissions to gain privileges via a symlink attack on a file with a predictable name. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.
Why it matters: CISA includes vulnerabilities in this catalog when there is evidence they are being actively exploited. An affected internet-facing or business-critical system deserves prompt attention.
What to do: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA remediation target: September 9, 2026.
Linux Kernel: Linux Kernel Out-of-Bounds Write Vulnerability
CVE-2022-0995 · Added by CISA August 26, 2026
What changed: Linux Kernel contains an out-of-bounds memory write vulnerability which could allow a local user to gain privileged access or cause a denial of service on the system.
Why it matters: CISA includes vulnerabilities in this catalog when there is evidence they are being actively exploited. An affected internet-facing or business-critical system deserves prompt attention.
What to do: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA remediation target: September 9, 2026.
Citrix NetScaler ADC and NetScaler Gateway: Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
CVE-2026-8452 · Added by CISA August 26, 2026
What changed: Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the bounds of a memory buffer vulnerability which could lead to denial of service.
Why it matters: CISA includes vulnerabilities in this catalog when there is evidence they are being actively exploited. An affected internet-facing or business-critical system deserves prompt attention.
What to do: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA remediation target: August 29, 2026.
Small-business action list
- Ask your IT provider whether any affected product is in your environment.
- Prioritize internet-facing, remote-access, identity, and backup systems.
- Apply vendor updates or mitigations after appropriate testing.
- Review privileged-account activity and confirm recoverable backups.
Verified source: CISA Known Exploited Vulnerabilities Catalog.
This edition is prepared automatically from CISA’s published data and provides general awareness, not an assessment of any specific organization.