CVE-2020-28948: Archive_Tar through 1.4.10 allows an unserialization attack because phar: is blocked but PHAR: is not blocked.

This week

HIGH 7.8WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2020-28948 is a high-severity flaw (CVSS 7.8) affecting archive tar, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Archive_Tar through 1.4.10 allows an unserialization attack because phar: is blocked but PHAR: is not blocked.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	47.5% (top 1%)
CISA exploited list	No
Weakness	CWE-502
Published	2020-11-19
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · drupal · fedoraproject · php

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

Am I affected?

Timeline

2020-11-19 19:15 UTCPublished CVE record published
2026-06-17 03:10 UTCUpdated Record last modified

php archive tar UPGRADE

Affected: < 1.4.11

Fixed in: 1.4.11

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy archive-tar || rpm -q archive-tar || archive-tar --version

2. UPGRADE to 1.4.11 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade archive-tar

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade archive-tar

Note

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

debian debian linux MITIGATE

Affected: 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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.

fedoraproject fedora MITIGATE

Affected: 32 · 33 · 34 · 35

Fixed in: no fixed release known

Safe to downgrade to: a release before 32

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.

drupal drupal UPGRADE

Affected: >= 7.0 and < 7.75 · >= 8.0.0 and < 8.9.10 · >= 8.8.0 and < 8.8.12 · >= 9.0.0 and < 9.0.9

Fixed in: 7.75, 8.8.12, 8.9.10, 9.0.9

Safe to downgrade to: a release before 7.0

1. Check installed version

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

2. UPGRADE to 7.75 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade drupal

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade drupal

Note

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

3. If no update is available yet, DOWNGRADE to a release before 7.0 (Debian / Ubuntu)

apt-cache madison drupal sudo apt install drupal=<VERSION_BEFORE_7.0> sudo apt-mark hold drupal

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list drupal sudo dnf downgrade drupal-<VERSION_BEFORE_7.0> sudo dnf versionlock add drupal

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-2020-28948?

archive tar: upgrade to 1.4.11; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-28948 being exploited?

CVE-2020-28948 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-2020-28948 affect?

CVE-2020-28948 affects archive tar, debian linux, fedora. Severity is high (CVSS 7.8). Archive_Tar through 1.4.10 allows an unserialization attack because phar: is blocked but PHAR: is not blocked.

How urgent is CVE-2020-28948?

Priority 62/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; On your watchlist

Software pages

Drupal vulnerabilities · PHP vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2021-32610 HIGH 7.1 UPGRADE MITIGATE In Archive_Tar before 1.4.14, symlinks can refer to targets outside of the extracted archive, a different vuln
CVE-2020-36193 HIGH 7.5 EXPLOITED UPGRADE MITIGATE PEAR Archive_Tar Improper Link Resolution Vulnerability
CVE-2020-28949 HIGH 7.8 EXPLOITED UPGRADE MITIGATE PEAR Archive_Tar Deserialization of Untrusted Data Vulnerability

References

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