CVE-2020-5202: apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP po

Q: How do I fix CVE-2020-5202?

apt-cacher-ng: upgrade to newer than 3.3; debian linux: mitigate or apply the listed mitigation; backports: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-5202 being exploited?

CVE-2020-5202 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-5202 affect?

CVE-2020-5202 affects apt-cacher-ng, debian linux, backports. Severity is medium (CVSS 5.5). apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port. The /usr/lib/apt-cacher-ng/acngtool program attempts to connect to apt-cacher-ng via TCP on localhost port 3142, even if the e

Q: How urgent is CVE-2020-5202?

Priority 39/100. Public exploit reference; On your watchlist

Routine

MEDIUM 5.5WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2020-5202 is a medium-severity flaw (CVSS 5.5) affecting apt-cacher-ng, debian linux, backports. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port. The /usr/lib/apt-cacher-ng/acngtool program attempts to connect to apt-cacher-ng via TCP on localhost port 3142, even if the explicit SocketPath=/var/run/apt-cacher-ng/socket command-line option is passed. The cron job /etc/cron.daily/apt-cacher-ng (which is active by default) attempts this periodically. Because 3142 is an unprivilege

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 59%)
CISA exploited list	No
Published	2020-01-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: apt-cacher-ng project · debian · opensuse

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

Am I affected?

Timeline

2020-01-21 18:15 UTCPublished CVE record published
2026-06-17 03:21 UTCUpdated Record last modified

apt-cacher-ng project apt-cacher-ng UPGRADE

Affected: <= 3.3

Fixed in: newer than 3.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 3.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade apt-cacher-ng

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade apt-cacher-ng

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse backports MITIGATE

Affected: sle-15 sp1

Fixed in: no fixed release known

Safe to downgrade to: a release before sle-15

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse leap MITIGATE

Affected: 15.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 15.1

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2020-5202?

apt-cacher-ng: upgrade to newer than 3.3; debian linux: mitigate or apply the listed mitigation; backports: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-5202 being exploited?

CVE-2020-5202 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-2020-5202 affect?

CVE-2020-5202 affects apt-cacher-ng, debian linux, backports. Severity is medium (CVSS 5.5). apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port. The /usr/lib/apt-cacher-ng/acngtool program attempts to connect to apt-cacher-ng via TCP on localhost port 3142, even if the e

How urgent is CVE-2020-5202?

Priority 39/100. Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities

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References

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