PatchTheCVECVE-2026-9538: Archive::Tar versions before 3.10 for Perl allow memory exhaustion via attacker controlled entry size field in
CVE-2026-9538 is a high-severity flaw (CVSS 7.5) affecting \. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Archive::Tar versions before 3.10 for Perl allow memory exhaustion via attacker controlled entry size field in tar header. _read_tar() reads each entry's payload with $handle->read($$data, $block), where $block is derived from the entry's 12-byte size field in the tar header with no upper bound on that value. A crafted header declaring a multi-gigabyte size causes Perl to allocate a scalar of that size.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.5% (top 56%) |
| CISA exploited list | No |
| Weakness | CWE-789 |
| Published | 2026-05-26 |
| Last modified | 2026-07-23 |
Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Advisories and coverage
Official advisories
- AlmaLinux Errata: [ALSA-2026:49525] Important: perl-Archive-Tar security update 2026-08-03
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-9538?
\: upgrade to 3.10. Exact commands for each OS are on this page.
Is CVE-2026-9538 being exploited?
CVE-2026-9538 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-9538 affect?
CVE-2026-9538 affects \. Severity is high (CVSS 7.5). Archive::Tar versions before 3.10 for Perl allow memory exhaustion via attacker controlled entry size field in tar header. _read_tar() reads each entry's payload with $handle->read($$data, $block), where $block is derived from the entry's
How urgent is CVE-2026-9538?
Priority 42/100. High severity; Remotely exploitable, no login, no user action
Software pages
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