CVE-2026-40973: High severity Spring Spring Boot vulnerability
A local attacker on the same host as the application may be able to take control of the directory used by ApplicationTemp. When server.servlet.session.persistent is set to true and the attack persists across application restarts, this may allow the attacker to read session information and hijack authenticated users or deploy a gadget chain and execute code as the application's user.
Affected: Spring Boot 4.0.0–4.0.5 (fix 4.0.6), 3.5.0–3.5.13 (fix 3.5.14), 3.4.0–3.4.15 (fix 3.4.16), 3.3.0–3.3.18 (fix 3.3.19), 2.7.0–2.7.32 (fix 2.7.33); predictable temp directory / ApplicationTemp ownership verification. Versions that are no longer supported are also affected per vendor advisory.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Spring Bootto a version that resolves this vulnerability.Fixed in 4.0.6 - Upgrade
Upgrade
Spring Bootto a version that resolves this vulnerability.Fixed in 3.5.14 - Upgrade
Upgrade
Spring Bootto a version that resolves this vulnerability.Fixed in 3.4.16 - Upgrade
Upgrade
Spring Bootto a version that resolves this vulnerability.Fixed in 3.3.19 - Upgrade
Upgrade
Spring Bootto a version that resolves this vulnerability.Fixed in 2.7.33 - Configuration
If the vulnerable predictable temp directory / `ApplicationTemp` ownership verification could be exploited, set `server.servlet.session.persistent` to `false` (the advisory notes risk when it is set to `true` and the attack persists across restarts).
Spring Boot server.servlet.session.persistent = false
Event History
Frequently Asked Questions
What is the severity of CVE-2026-40973?
CVE-2026-40973 is rated as a high severity vulnerability due to its potential to allow local attackers to read session information.
How do I fix CVE-2026-40973?
To remediate CVE-2026-40973, ensure that the `server.servlet.session.persistent` configuration is set to false.
What versions of Spring Boot are affected by CVE-2026-40973?
CVE-2026-40973 affects Spring Boot versions from 2.7.0 up to 2.7.32, 3.3.0 up to 3.3.18, 3.4.0 up to 3.4.15, 3.5.0 up to 3.5.13, and 4.0.0 up to 4.0.5.
Can CVE-2026-40973 be exploited remotely?
No, CVE-2026-40973 requires a local attacker to be on the same host as the application to exploit the vulnerability.
What are the potential consequences of CVE-2026-40973?
If exploited, CVE-2026-40973 could allow an attacker to gain unauthorized access to session information, which may lead to further compromise of the application.