PatchTheCVECVE-2020-28949: PEAR Archive_Tar Deserialization of Untrusted Data Vulnerability
87
Patch now
HIGH 7.8EXPLOITEDWATCHLISTUPGRADEMITIGATEMITIGATE
CVE-2020-28949 is a high-severity flaw (CVSS 7.8) affecting archive tar, debian linux, fedora, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Archive_Tar through 1.4.10 has :// filename sanitization only to address phar attacks, and thus any other stream-wrapper attack (such as file:// to overwrite files) can still succeed.
Why this priority
- High severity
- EPSS top 1%: very likely to be exploited
- Exploited in the wild (CISA KEV)
- 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 | 84.6% (top 1%) |
| CISA exploited list | Yes, fix due 2022-09-15 |
| Published | 2020-11-19 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Exploited Added to the CISA Known Exploited Vulnerabilities list
- Deadline CISA due date for US federal agencies to patch
- Updated Record last modified
php archive tar UPGRADE
Affected: < 1.4.12
Fixed in: 1.4.12
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 1.4.12 (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.
Exact fixes by distribution
A distro patch exists: prefer upgrading over downgrading.
Composer (PHP) · pear/archive_tar · FIXED · 1.4.11 · vulnerable: < 1.4.11 · source
composer require "pear/archive_tar:>=1.4.11"
Fedora 46 · feh · FIXED · 3.13.1-1.fc46 · FEDORA-2026-3c76a13a4f · source
sudo dnf upgrade --advisory=FEDORA-2026-3c76a13a4f
Fedora ELN · setroubleshoot · FIXED · 3.3.37-7.eln159 · FEDORA-2026-f81b122fe1 · source
sudo dnf upgrade --advisory=FEDORA-2026-f81b122fe1
Ubuntu 20.04 · php-pear · FIXED · 1:1.10.9+submodules+notgz-1ubuntu0.20.04.1
sudo apt update && sudo apt install --only-upgrade php-pear
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' php-pear)" ge "1:1.10.9+submodules+notgz-1ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 22.04 · php-pear · FIXED · 1:1.10.9+submodules+notgz-1ubuntu1
sudo apt update && sudo apt install --only-upgrade php-pear
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' php-pear)" ge "1:1.10.9+submodules+notgz-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.04 · php-pear · FIXED · 1:1.10.9+submodules+notgz-1ubuntu1
sudo apt update && sudo apt install --only-upgrade php-pear
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' php-pear)" ge "1:1.10.9+submodules+notgz-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.10 · php-pear · FIXED · 1:1.10.9+submodules+notgz-1ubuntu1
sudo apt update && sudo apt install --only-upgrade php-pear
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' php-pear)" ge "1:1.10.9+submodules+notgz-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · php-pear · FIXED · 1:1.10.9+submodules+notgz-1.1
sudo apt update && sudo apt install --only-upgrade php-pear
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' php-pear)" ge "1:1.10.9+submodules+notgz-1.1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · php-pear · FIXED · 1:1.10.9+submodules+notgz-1.1
sudo apt update && sudo apt install --only-upgrade php-pear
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' php-pear)" ge "1:1.10.9+submodules+notgz-1.1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 7 · php-pear · FIXED · php-pear-1.9.4-23.el7_9
sudo dnf upgrade --advisory=RHSA-2022:7340
rpm -q php-pear
RHEL 6 · php-pear · DEFERRED
RHEL 8 · php:7.2/php-pear · DEFERRED
RHEL 8 · php:7.3/php-pear · DEFERRED
Alpine 3.20 · drupal7 · FIXED · drupal7-7.75-r0
apk add --upgrade drupal7
apk info -v drupal7
sudo yum update --advisory=ALAS2-2021-1584
sudo yum update --advisory=ALAS-2021-1466
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: github.com/pear/Archive_Tar/issues/33
- GitHub PoC: 0x240x23elu/CVE-2020-28948-and-CVE-2020-28949
- GitHub PoC: JinHao-L/PoC-for-CVE-2020-28948-CVE-2020-28949
- Metasploit: PEAR Archive_Tar 1.4.10 Arbitrary File Write
Verify at the official source NVD · CVE Program · CISA KEV catalog · 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.
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-2020-28949?
archive tar: upgrade to 1.4.12; 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-2020-28949 being exploited?
Yes. CVE-2020-28949 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.
What does CVE-2020-28949 affect?
CVE-2020-28949 affects archive tar, debian linux, fedora. Severity is high (CVSS 7.8). Archive_Tar through 1.4.10 has :// filename sanitization only to address phar attacks, and thus any other stream-wrapper attack (such as file:// to overwrite files) can still succeed.
How urgent is CVE-2020-28949?
Priority 87/100. High severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); 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-2020-28948 HIGH 7.8 UPGRADE MITIGATE Archive_Tar through 1.4.10 allows an unserialization attack because phar: is blocked but PHAR: is not blocked.