Vulnerability · Published May 27, 2026 · Assigned by CPANSec
CVE-2026-48959IO::Uncompress::Unzip versions before 2.220 for Perl allow CPU exhaustion via per-byte read loop in fastForward
High 7.5
In plain English
A high-severity security flaw in IO::Uncompress::Unzip from PMQS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
IO::Uncompress::Unzip versions before 2.220 for Perl allow CPU exhaustion via per-byte read loop in fastForward. fastForward() compares length $offset (the digit count of the offset, 1 to 19) against the chunk size $c instead of $offset itself, so $c shrinks from 16 KiB to 1-19 bytes per iteration. Extracting a named entry from an attacker supplied zip via IO::Uncompress::Unzip->new($zip, Name => $target) drives a per-byte read loop scaling with the entry's compressed size, up to the non-Zip64 4 GiB cap.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | perl | 5.42.3-r0 | ALPINE-CVE-2026-48959 |
| Debian:12 | libio-compress-perl | 2.204-1+deb12u1 | DEBIAN-CVE-2026-48959 |
| Debian:13 | libio-compress-perl | 2.213-1+deb13u1 | DEBIAN-CVE-2026-48959 |
| Debian:14 | libio-compress-perl | 2.220-1 | DEBIAN-CVE-2026-48959 |
| Debian:12 | perl | 5.36.0-7+deb12u4 | DEBIAN-CVE-2026-48959 |
| Debian:13 | perl | 5.40.1-6+deb13u1 | DEBIAN-CVE-2026-48959 |
| Debian:14 | perl | 5.40.1-8 | DEBIAN-CVE-2026-48959 |
| Ubuntu:22.04:LTS | libio-compress-perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:24.04:LTS | libio-compress-perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:25.10 | libio-compress-perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:26.04:LTS | libio-compress-perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:26.10 | libio-compress-perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:22.04:LTS | perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:24.04:LTS | perl | 5.38.2-3.2ubuntu0.4 | USN-8684-1 |
| Ubuntu:24.04:LTS | perl | 5.38.2-3.2ubuntu0.4 | UBUNTU-CVE-2026-48959 |
| Ubuntu:25.10 | perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:26.04:LTS | perl | no fix listed | UBUNTU-CVE-2026-48959 |
| Ubuntu:26.10 | perl | no fix listed | UBUNTU-CVE-2026-48959 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| PMQS | IO::Uncompress::Unzip | 0 – before 2.220 |
Weakness: CWE-407 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H