CVE-2026-40973 Spring Boot accepts predictable temp directory without ownership verification
Local attackers can hijack sessions or execute code by exploiting predictable temporary directories in Spring Boot when persistent sessions are enabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40973?
CVE-2026-40973 is a high-severity path traversal vulnerability in Spring Boot, published on 27 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-377
Which versions are affected by CVE-2026-40973?
10 open source packages ship an affected version, including org.springframework.boot:spring-boot. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.springframework.boot:spring-boot Maven | All versions to 2.7.32 | None |
org.springframework.boot:spring-boot Maven | All versions to 2.7.32 | None |
org.springframework.boot:spring-boot Maven | From 3.3.0 to 3.3.18 | None |
org.springframework.boot:spring-boot Maven | From 3.3.0 to 3.3.18 | None |
org.springframework.boot:spring-boot Maven | From 3.4.0 to 3.4.15 | None |
org.springframework.boot:spring-boot Maven | From 3.4.0 to 3.4.15 | None |
4 more packages
org.springframework.boot:spring-boot Maven | From 3.5.0 | 3.5.14 |
org.springframework.boot:spring-boot Maven | From 3.5.0 | 3.5.14 |
org.springframework.boot:spring-boot Maven | From 4.0.0 | 4.0.6 |
org.springframework.boot:spring-boot Maven | From 4.0.0 | 4.0.6 |
Products include Vmware Spring Boot.
How do I fix CVE-2026-40973?
Upgrade org.springframework.boot:spring-boot to a fixed version for your release line: 3.5.14 or 4.0.6.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-40973 being exploited?
There is no known exploitation of CVE-2026-40973 in the wild and no public exploit code.
Other vulnerabilities in Spring Boot
- CVE-2023-20873 Spring Boot Security Bypass with Wildcard Pattern Matching on Cloud Foundry
- CVE-2026-40976 Spring Boot's default security filter chain has no authorization rule with Actuator but without Health
- CVE-2026-22731 Authentication Bypass under Actuator Health groups paths
- CVE-2026-22733 Authentication Bypass under Actuator CloudFoundry endpoints
- CVE-2022-27772 Temporary Directory Hijacking to Local Privilege Escalation Vulnerability in org.springframework.boot:spring-boot
Sources
Also known as CLEANSTART-2026-DZ11796, CLEANSTART-2026-UX96534, CLSA-2026-1779065187, CLSA-2026-1779410900, ECHO-1e6e-2e1a-3941, GHSA-wwpq-f5c3-7hvx and 8 more.