CVE-2026-40977

Local file corruption via PID-file symlink

Published Apr 27, 2026 · Updated Apr 27, 2026

Link-following in ApplicationPidFileWriter in Spring Boot allows local users to corrupt one host file through a crafted PID-file symlink. On application startup, the writer opens the predictable PID-file path for output without rejecting a symbolic link, so the process overwrites the link target with its PID. Exploitation requires ApplicationPidFileWriter to be configured and the local user to have write access to the PID file's directory; each startup can corrupt one chosen file writable by the application.

CVSS severity4.7
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Link-following in ApplicationPidFileWriter in Spring Boot allows local users to corrupt one host file through a crafted PID-file symlink. On application startup, the writer opens the predictable PID-file path for output without rejecting a symbolic link, so the process overwrites the link target with its PID. Exploitation requires ApplicationPidFileWriter to be configured and the local user to have write access to the PID file's directory; each startup can corrupt one chosen file writable by the application.

The record

CVE
CVE-2026-40977
Published
Apr 27, 2026
Updated
Apr 27, 2026
Vendor
Spring
Product
Spring Boot
Classifications
CWE-59, CAPEC-132, CAPEC-35, CAPEC-76, CAPEC-17
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.7.0 <2.7.33
  2. Affected versionversion=3.3.0 <3.3.19
  3. Affected versionversion=3.4.0 <3.4.16
  4. Affected versionversion=3.5.0 <3.5.14
  5. Affected versionversion=4.0.0 <4.0.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Spring · Spring Bootversion=2.7.0 <2.7.33; version=3.3.0 <3.3.19; version=3.4.0 <3.4.16; version=3.5.0 <3.5.14; version=4.0.0 <4.0.6

Published CVSS scores

6.7NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.7GitHubCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
CAPEC-132Symlink Attack
CAPEC-35Leverage Executable Code in Non-Executable Files
CAPEC-76Manipulating Web Input to File System Calls
CAPEC-17Using Malicious Files

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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