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Response snapshot Nov 4, 2026, 16:41 UTC

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VulnerabilityCVE-2026-13048

Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language...

Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language attribute into the catalog filename. load_lexicon builds the catalog path by appending Messages/$lang.

At a glance

Exploited
Not known
Severity
8.2 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-13048 (opens a new tab)

What happened

Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language attribute into the catalog filename.

load_lexicon builds the catalog path by appending Messages/$lang.po to the directory holding Localizer.pm, where $lang is the language attribute, with no check that it names a bare locale tag. A value holding ../ segments walks out of the message directory, so any readable path with a .po suffix is loaded.

While parsing the catalog, extract_header_msgstr takes the Plural-Forms: header, prefixes $ to the bare words nplurals, plural and n, and passes the rest verbatim into a string that is evaluated: the nplurals form evaluates the header expression immediately, and the plural_code form compiles it into a subroutine whose body runs when a plural message is localized. A header of nplurals=2; plural=(system('...')

,0); therefore runs that command as the catalog loads. The evaluation inherits strict, so an expression that assigns to an undeclared variable fails to compile, while one built from calls alone does not.

Continue reading

An application that sets the language attribute from request data, an Accept-Language header or a locale parameter, and an attacker who can place a file with a .po suffix and chosen contents at a readable path, together give code execution as the application user. The message expansion path is not affected: expand_named substitutes only the placeholder names the caller supplies, and _mangle_value returns the value unchanged.

Scores and how they were measured

CVSS base severity

8.2

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-13048 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 4). Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language... (CVE-2026-13048). https://kevwire.com/record/CVE-2026-13048

MLA

"Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language... (CVE-2026-13048)." KEVWire, 4 Nov. 2026, kevwire.com/record/CVE-2026-13048.

Chicago

KEVWire. "Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language... (CVE-2026-13048)." Last modified November 4, 2026. https://kevwire.com/record/CVE-2026-13048.

Evidence summary (plain text)

Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language... (Aug 13, 2026).
Data::MuForm::Localizer versions through 0.05 for Perl execute Perl from a message catalog header, reached at an arbitrary path because load_lexicon interpolates the language attribute into the catalog filename.

load_lexicon builds the catalog path by appending Messages/$lang.po to the directory holding Localizer.pm, where $lang is the language attribute, with no check that it names a bare locale tag. A value holding ../ segments walks out of the message directory, so any readable path with a .po suffix is loaded.
CVSS 8.2 (version 3.1; evidence as of Nov 4, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-13048).
Sources:
NVD CVE-2026-13048: https://nvd.nist.gov/vuln/detail/CVE-2026-13048
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T15:01:12.676Z&lastModEndDate=2026-11-04T16:35:56.849Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T14:26:01.015Z&lastModEndDate=2026-11-04T16:00:58.963Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T13:51:03.554Z&lastModEndDate=2026-11-04T15:25:56.002Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-13048.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 4, 2026, 16:35 UTC. Ingestion is not an independent editorial investigation.

NVD status: Deferred. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail