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Full vulnerability report · 2026
CVE-2026-48959High confidence

IO::Uncompress::Unzip versions before 2.220 for Perl allow CPU exhaustion via per-byte read loop in fastForward

PMQS · IO::Uncompress::Unzip

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

2 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivelibio-compress-perlUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiveperlVendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.5.38.2-3.2ubuntu0.4Canonical record ↗Source updated 10 Sept 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-32043

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

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.

What

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.

Why

An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Inefficient Algorithmic Complexity → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-407

CWE-407: Inefficient Algorithmic Complexity. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-407
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2026-2858IBM AIX und VIOS: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in IBM AIX und IBM VIOS ausnutzen, um beliebigen Programmcode auszuführen, um seine Privilegien zu erhöhen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, und um Sicherheitsvorkehrungen zu umgehen.

Official advisory
CERT-FR · French · CERTFR-2026-AVI-1067Multiples vulnérabilités dans les produits IBM

d?id=CVE-2026-47010 Référence CVE CVE-2026-47021 https://www.cve.org/CVERecord?id=CVE-2026-47021 Référence CVE CVE-2026-47027 https://www.cve.org/CVERecord?id=CVE-2026-47027 Référence CVE CVE-2026-47057 https://www.cve.org/CVERecord?id=CVE-2026-47057 Référence CVE CVE-2026-47058 https://www.cve.org/CVERecord?id=CVE-2026-47058 Référence CVE CVE-2026-47059 https://www.cve.org/CVERecord?id=CVE-2026-47059 Référence CVE CVE-2026-47063 https://www.cve.org/CVERecord?id=CVE-2026-47063 Référence CVE CVE-2026-47244 https://www.cve.org/CVERecord?id=CVE-2026-47244 Référence CVE CVE-2026-48043 https://www.cve.org/CVERecord?id=CVE-2026-48043 Référence CVE CVE-2026-48959 https://www.cve.org/CVERecord?id=CVE-2026-48959 Référence CVE CVE-2026-48962 https://www.cve.org/CVERecord?id=CVE-2026-48962 Référence CVE CVE-2026-50560 https://www.cve.org/CVERecord?id=CVE-2026-50560 Référence CVE CVE-2026-50645 https://www.cve.org/CVERecord?id=CVE-2026-50645 Référence CVE CVE-2026-54225 https://www.cve.org/CVERecord?id=CVE-2026-54225 Référence CVE CVE-2026-57819 https://www.cve.org/CVERecord?id=CVE-2026-57819 Référence CVE CVE-2026-59879 https://www.cve.org/CVERecord?id=CVE-2026-59879 Référence CVE CVE-2026-59880 https://www.cve.org/CVERecord?id=CVE-2026-59880 Référence CVE CVE-2026-59995 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0731Multiples vulnérabilités dans les produits Microsoft

mai 2026 Bulletin de sécurité Microsoft CVE-2026-46230 du 29 mai 2026 Bulletin de sécurité Microsoft CVE-2026-46231 du 29 mai 2026 Bulletin de sécurité Microsoft CVE-2026-46233 du 29 mai 2026 Bulletin de sécurité Microsoft CVE-2026-46234 du 29 mai 2026 Bulletin de sécurité Microsoft CVE-2026-46236 du 29 mai 2026 Bulletin de sécurité Microsoft CVE-2026-46238 du 29 mai 2026 Bulletin de sécurité Microsoft CVE-2025-15649 du 31 mai 2026 Bulletin de sécurité Microsoft CVE-2026-42789 du 31 mai 2026 Bulletin de sécurité Microsoft CVE-2026-42790 du 31 mai 2026 Bulletin de sécurité Microsoft CVE-2026-48962 du 31 mai 2026 Bulletin de sécurité Microsoft CVE-2026-48959 du 02 juin 2026 Bulletin de sécurité Microsoft CVE-2026-50031 du 04 juin 2026 Bulletin de sécurité Microsoft CVE-2026-46273 du 05 juin 2026 Bulletin de sécurité Microsoft CVE-2026-50292 du 06 juin 2026 Bulletin de sécurité Microsoft CVE-2026-26142 du 09 juin 2026 Bulletin de sécurité Microsoft CVE-2026-33113 du 09 juin 2026 Bulletin de sécurité Microsoft CVE-2026-40371 du 09 juin 2026 Bulletin de sécurité Microsoft CVE-2026-40376 du 09 juin 2026 Bulletin de sécurité Microsoft CVE-2026-42835 du 09 juin 2026 Bulletin de sécurité Microsoft CVE-2026-42902 du 09 juin 2026 Bulletin de sécurité Microsoft CVE-2026-44819 du 09 juin 2026 Bulletin de s

Official advisory
NCSC-NL · Dutch · NCSC-2026-0321Meerdere kwetsbaarheden verholpen in IBM AIX en IBM PowerVM VIOS

IO::Uncompress::Unzip versions prior to 2.220 for Perl contain a vulnerability in the fastForward() function that causes a per-byte read loop, leading to CPU exhaustion when processing malicious zip files.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
< 2.220
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 27 May 2026 · Last source change 29 May 2026, 15:50 UTC · CWE-407 · Inefficient Algorithmic Complexity

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-32043
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-48959 · cve.blacktree.nl