CVE-2015-3999: Piriform CCleaner 3.26.0.1988 through 5.02.5101 writes the filenames to disk when overwriting files, which all

Routine

LOW 2.1DOWNGRADE

CVE-2015-3999 is a low-severity flaw (CVSS 2.1) affecting ccleaner. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Piriform CCleaner 3.26.0.1988 through 5.02.5101 writes the filenames to disk when overwriting files, which allows local users to obtain sensitive information by searching unallocated disk space.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	2.1 (Low)
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-200
Published	2015-05-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: piriform

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2015-05-20 18:59 UTCPublished CVE record published
2026-06-17 00:26 UTCUpdated Record last modified

piriform ccleaner DOWNGRADE

Affected: 3.26.1888 · 3.27.1900 · 3.28.1913 · 4.00.4064 · 4.01.4093 · 4.02.4115 · 4.03.4151 · 4.04.4197

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.26.1888

1. Check installed version

apt-cache policy ccleaner || rpm -q ccleaner || ccleaner --version

2. No fixed release: DOWNGRADE to a release before 3.26.1888 (Debian / Ubuntu)

apt-cache madison ccleaner sudo apt install ccleaner=<VERSION_BEFORE_3.26.1888> sudo apt-mark hold ccleaner

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

dnf --showduplicates list ccleaner sudo dnf downgrade ccleaner-<VERSION_BEFORE_3.26.1888> sudo dnf versionlock add ccleaner

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-2015-3999?

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

Is CVE-2015-3999 being exploited?

CVE-2015-3999 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-2015-3999 affect?

CVE-2015-3999 affects ccleaner. Severity is low (CVSS 2.1). Piriform CCleaner 3.26.0.1988 through 5.02.5101 writes the filenames to disk when overwriting files, which allows local users to obtain sensitive information by searching unallocated disk space.

How urgent is CVE-2015-3999?

Priority 18/100. No elevated risk signals yet.

References

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