CVE-2026-5525: A stack-based buffer overflow vulnerability exists in Notepad++ version 8.9.3 in the file drop handler compone

Routine

MEDIUM 6.0DOWNGRADE

CVE-2026-5525 is a medium-severity flaw (CVSS 6.0) affecting notepad\+\+. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A stack-based buffer overflow vulnerability exists in Notepad++ version 8.9.3 in the file drop handler component. When a user drags and drops a directory path of exactly 259 characters without a trailing backslash, the application appends a backslash and null terminator without proper bounds checking, resulting in a stack buffer overflow and application crash (STATUS_STACK_BUFFER_OVERRUN).

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.0 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-04-10
Last modified	2026-10-26

Publisher (CNA): securin · Vendor: notepad-plus-plus

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-10 08:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

notepad-plus-plus notepad\+\+ DOWNGRADE

Affected: 8.9.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.9.3

1. Check installed version

apt-cache policy notepad++ || rpm -q notepad++ || notepad++ --version

2. No fixed release: DOWNGRADE to a release before 8.9.3 (Debian / Ubuntu)

apt-cache madison notepad++ sudo apt install notepad++=<VERSION_BEFORE_8.9.3> sudo apt-mark hold notepad++

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list notepad++ sudo dnf downgrade notepad++-<VERSION_BEFORE_8.9.3> sudo dnf versionlock add notepad++

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-5525?

notepad\+\+: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-5525 being exploited?

CVE-2026-5525 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-5525 affect?

CVE-2026-5525 affects notepad\+\+. Severity is medium (CVSS 6.0). A stack-based buffer overflow vulnerability exists in Notepad++ version 8.9.3 in the file drop handler component. When a user drags and drops a directory path of exactly 259 characters without a trailing backslash, the application appends a

How urgent is CVE-2026-5525?

Priority 27/100. Public exploit reference

Software pages

Notepad++ vulnerabilities

References

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