Analyst readout for executives and security teams
Plain-English summary
A malformed tar archive can make vulnerable Perl Archive::Tar versions allocate excessive memory while reading an entry. The practical impact is denial of service: a process that accepts or scans untrusted tar files may run out of memory or crash.
Executive priority
Treat as a targeted denial-of-service risk. It is not shown as actively exploited, but externally supplied archive processing should be patched promptly because failures may affect availability.
Technical view
Archive::Tar before 3.10 derives an entry read size from the tar header size field without an upper bound. In _read_tar(), that value reaches a read into a Perl scalar, allowing attacker-controlled oversized allocation. This maps to CWE-789: uncontrolled memory allocation.
Likely exposure
Exposure is most likely in Perl applications, automation, package-processing jobs, or security scanners that use Archive::Tar to process tar archives from users, partners, CI artifacts, or other untrusted sources.
Exploitation context
The bundle does not show KEV listing, CVSS scoring, or confirmed active exploitation. Exploitation would require the target to parse a crafted tar archive with a vulnerable Archive::Tar version.
Researcher notes
The source bundle identifies the vulnerable behavior and a 3.10 release/patch reference, but provides no CVSS vector, affected CPEs, exploit telemetry, or distribution-specific fixed package data.
Mitigation direction
- Upgrade Archive::Tar or Archive-Tar to version 3.10 or later.
- Prioritize systems that process untrusted tar archives automatically.
- Apply memory limits around archive-processing workers where practical.
- Check vendor or distribution advisories for backported fixes.
Validation and detection
- Inventory Perl dependencies for Archive::Tar or Archive-Tar versions before 3.10.
- Identify services and jobs that parse tar archives from untrusted sources.
- Confirm upgraded hosts load the fixed module version.
- Review logs for archive-processing crashes or memory exhaustion events.
Public sources used
Based on public source material and reviewed before publication.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-789: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-9538 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timeline CPANSec
Issue reported.
- Source timeline CPANSec
Version 3.10 released.
- CVE reserved CVE Program
The CVE ID was reserved by the assigning CNA.
- CVE published CVE Program
The CVE record was published.
- CVE updated CVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 source CVE List V5
- https://github.com/jib/archive-tar-new/commit/f9af01426038e29d9578825a0cd3626946ab08c7.patch CVE reference, CPANSec · patch
- https://metacpan.org/release/BINGOS/Archive-Tar-3.10/changes CVE reference, CPANSec · release-notes
- http://www.openwall.com/lists/oss-security/2026/05/26/4 CVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Memory Allocation with Excessive Size Value
Memory Allocation with Excessive Size Value represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.