CVE-2020-28948 — pear/archive_tar
HIGHCVE-2020-28948 is a high-severity (CVSS 7.8) Deserialization of Untrusted Data vulnerability in pear/archive_tar. 5 public exploit references exist, so weaponization risk is real. A fix is available for pear/archive_tar — see the affected versions and patch details below.
Multiple vulnerabilities through filename manipulation in Archive_Tar
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2020-28948 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
pear/archive_tarReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Archive_Tar through 1.4.10 allows an unserialization attack because phar: is blocked but PHAR: is not blocked.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | pear/archive_tar | all versions | 1.4.11composer require pear/archive_tar:^1.4.11 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pear/archive_tar, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pear/archive_tar to 1.4.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-28948 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-28948 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2020-28948. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
PHP 7.2 and 7.3 marked End of Life at the time this CVE was released. There would be no patches made available for php-pear.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 7 | php-pear-1:1.9.4-23.el7_9 | RHSA-2022:7340 |
| Red Hat Enterprise Linux 8 | php:7.4-8060020220907094815.5caa48ff | RHSA-2022:6542 |
| Red Hat Enterprise Linux 8.4 Extended Update Support | php:7.4-8040020220907095003.d7c09045 | RHSA-2022:6541 |
Frequently Asked Questions
Is CVE-2020-28948 in your dependencies?
O3 Security finds CVE-2020-28948 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.