CVE-2026-48590Public exploit

XML markup injection via unvalidated name interpolation

Published Aug 21, 2026 · Updated Aug 21, 2026

XML injection in Joshua Nussbaum xml_builder before 2.4.1 allows attackers to inject arbitrary markup through crafted name arguments. XmlBuilder.format/2, format_attributes/1, and doctype serialization interpolate element names, attribute keys, and identifiers without validating or escaping XML structural characters. Exploitation requires attacker-influenced data to reach a name position; injected elements, comments, or event-handler attributes can corrupt output or affect downstream consumers.

CVSS severity2.1
Low
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XML injection in Joshua Nussbaum xml_builder before 2.4.1 allows attackers to inject arbitrary markup through crafted name arguments. XmlBuilder.format/2, format_attributes/1, and doctype serialization interpolate element names, attribute keys, and identifiers without validating or escaping XML structural characters. Exploitation requires attacker-influenced data to reach a name position; injected elements, comments, or event-handler attributes can corrupt output or affect downstream consumers.

The record

CVE
CVE-2026-48590
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
Joshua Nussbaum
Product
xml_builder
Classifications
CWE-91, CAPEC-250, T1059.007
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.0.1 <2.4.1
  2. Affected versionversion=9fb49131ad3ee146a4c9db9bc175bdffe32e30a0 <d5c0aec32a8eecbb440fb9bbb0f59d4d188d5859

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Joshua Nussbaum · xml_builderversion=0.0.1 <2.4.1; version=9fb49131ad3ee146a4c9db9bc175bdffe32e30a0 <d5c0aec32a8eecbb440fb9bbb0f59d4d188d5859

Published CVSS scores

2.1GitHubCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-91XML Injection (aka Blind XPath Injection)
CAPEC-250XML Injection
T1059.007JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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