CVE-2020-28949 — PEAR Archive_Tar Deserialization of Untrusted Data Vulnerability
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Confirmed exploitation (CISA KEV)+35
- Public exploit/PoC (metasploit)+12
- EPSS 84.6% (30-day exploitation probability)+15
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Composer Pear/archive Tar: fixed in version 1.4.11 — github.com (GitHub Security Advisories)
CISA required action CISA
Apply updates per vendor instructions.
US federal deadline: Sep 15, 2022 — passed 1492 day(s) ago
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Drupal Drupal, Fedoraproject Fedora…).
- Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
- Apply the fixed version or the patch documented under Remediation.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Debian | Debian Linux | version 9.0version 10.0 | Vulnerable | NIST National Vulnerability Database |
| Drupal | Drupal | ≥ 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 | Vulnerable | NIST National Vulnerability Database |
| Fedoraproject | Fedora | version 32version 33version 34version 35 | Vulnerable | NIST National Vulnerability Database |
| Php | Archive Tar | < 1.4.12 | Vulnerable | NIST National Vulnerability Database |
| Composer | Pear/archive Tar | < 1.4.11 | Vulnerable | GitHub Security Advisories |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.8 | CVSS 3.1 | High | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
| 6.8 | CVSS 2.0 | Medium | 8.6 | 6.4 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) CISA KEV details CISA
CISA lists a CVE once it has evidence of exploitation against real targets.
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.
Public exploits, PoCs and detection templates
Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.
- PEAR Archive_Tar 1.4.10 Arbitrary File Write excellent Nov 17, 2020
Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 84.55%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Hunt retroactively in logs from before Aug 25, 2022 (KEV listing): exploitation may have started earlier.
Timeline
What happened to this CVE, newest first.
- 2026
- Fix documented
- Affected products added · composer/pear/archive tar
- Affected products added · php/archive tar, debian/debian linux, fedoraproject/fedora, drupal/drupal
- Source status changed · Published → Analyzed
- Record published
- CVSS changed · 7.8
- Source status changed · → Published
- SSVC assessment updated
- Added to CISA KEV (detected)
- Record created in this database
- 2022
- Added to CISA KEV catalog
- 2020
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 3× References added · Oct 13, 2026 – Oct 13, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
29 on the record
- github.com/pear/Archive_Tar/issues/33
- www.cisa.gov/known-exploited-vulnerabilities-catalog
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5KSF
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5KSF
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VJQQYD
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/42GP
- packetstormsecurity.com/files/161095/PEAR-Archive_Tar-Arbitrary-File-Write.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VJQQ
- security.gentoo.org/glsa/202101-23
- github.com/advisories/GHSA-75c5-f4gw-38r9
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KWM4CT
- lists.debian.org/debian-lts-announce/2020/11/msg00045.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VJQQ
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/42GPGV
- www.drupal.org/sa-core-2020-013
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/42GP
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4V35
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NBYZ
- github.com/FriendsOfPHP/security-advisories/blob/master/pear/archive_tar/CVE-202
- nvd.nist.gov/vuln/detail/CVE-2020-28949
- github.com/pear/Archive_Tar/commit/0670a05fdab997036a3fc3ef113b8f5922e574da
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4V35LB
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KWM4
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KWM4
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4V35
- www.debian.org/security/2020/dsa-4817
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NBYZSH
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NBYZ
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5KSFM6
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
- Medium CVE-2026-55808 Drupal core - Moderately critical - Improper validation - SA-CORE-2026-009 Jul 10, 2026
- Medium CVE-2026-55803 Drupal core - Critical - PHP object injection - SA-CORE-2026-005 Jul 10, 2026
- Medium CVE-2026-55804 Drupal core - Moderately critical - Gadget chain - SA-CORE-2026-006 Jul 10, 2026
- Low CVE-2026-55807 Drupal core - Moderately critical - Server-side request forgery - SA-CORE-2026-008 Jul 10, 2026
- Medium CVE-2026-55806 Drupal core - Less critical - Cache poisoning and open redirect - SA-CORE-2026-007 Jul 10, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2020-28949 is "PEAR Archive_Tar Deserialization of Untrusted Data Vulnerability", rated High. It affects Debian Linux (Debian); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.8 describes technical severity. EPSS 84.55% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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