CVE-2025-11147: Reflected cross-site scripting (XSS) in Apt-Cacher-NG v3.2.1

Routine

MEDIUM 5.4DOWNGRADE

CVE-2025-11147 is a medium-severity flaw (CVSS 5.4) affecting apt-cacher-ng. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Reflected cross-site scripting (XSS) in Apt-Cacher-NG v3.2.1. The vulnerability allows malicious scripts (XSS) to be executed in “/html/<filename>.html”.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-09-29
Last modified	2026-10-19

Publisher (CNA): Spanish National Cybersecurity Institute, S.A. (INCIBE) · Vendor: apt-cacher-ng project

Last updated 2026-10-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-09-29 10:15 UTCPublished CVE record published
2026-10-19 16:10 UTCUpdated Record last modified

apt-cacher-ng project apt-cacher-ng DOWNGRADE

Affected: 3.2-1

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.2-1

1. Check installed version

apt-cache policy apt-cacher-ng || rpm -q apt-cacher-ng || apt-cacher-ng --version

2. No fixed release: DOWNGRADE to a release before 3.2-1 (Debian / Ubuntu)

apt-cache madison apt-cacher-ng sudo apt install apt-cacher-ng=<VERSION_BEFORE_3.2-1> sudo apt-mark hold apt-cacher-ng

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

dnf --showduplicates list apt-cacher-ng sudo dnf downgrade apt-cacher-ng-<VERSION_BEFORE_3.2-1> sudo dnf versionlock add apt-cacher-ng

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-2025-11147?

apt-cacher-ng: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-11147 being exploited?

CVE-2025-11147 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-2025-11147 affect?

CVE-2025-11147 affects apt-cacher-ng. Severity is medium (CVSS 5.4). Reflected cross-site scripting (XSS) in Apt-Cacher-NG v3.2.1. The vulnerability allows malicious scripts (XSS) to be executed in “/html/<filename>.html”.

How urgent is CVE-2025-11147?

Priority 21/100. No elevated risk signals yet.

Related CVEs

CVE-2025-11146 MEDIUM 5.4 DOWNGRADE Reflected Cross-site scripting (XSS) in Apt-Cacher-NG v3.2.1

References

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