CVE-2026-40203
3.7 · LOWOverview
CVE-2026-40203 is a low-severity vulnerability. It was published on August 28, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Frequently Asked Questions
What is CVE-2026-40203?
CVE-2026-40203 is a low-severity vulnerability. It was published on August 28, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
How severe is CVE-2026-40203?
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-40203?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-40203?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-40203 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
Related LOW CVEs from 2026
View all →Improper handling of values in the microcode flow for some Intel(R) Processor Family may allow an es
A flaw was found in libsoup, a library used by applications to send network requests. This vulnerabi
A flaw was found in libsoup. A remote attacker, by controlling the method parameter of the `soup_mes
A flaw was found in libsoup. An attacker controlling the value used to set the Content-Type header c
OpenSC is an open source smart card tools and middleware. Prior to version 0.27.0, feeding a crafted
OpenSC is an open source smart card tools and middleware. Prior to version 0.27.0, sc_compacttlv_fin
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and C
HCL BigFix Service Management (SM) is susceptible to a Root File System Not Mounted as Read-Only. An
FacturaScripts is an open source accounting and invoicing software. Versions 2025.7 and prior contai
An integer underflow in the volxlate function in Netatalk 3.0.0 through 4.4.2 allows a local privile
Capsule is a multi-tenancy and policy-based framework for Kubernetes. To defend against namespace hi
Improper input validation in Microsoft Azure Attestation service and Device Health Attestation Servi