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NVD / CVE Program· CNA GitHub_M

CVE-2026-83618: xmldom: requireWellFormed DocType publicId/systemId validation is bypassable via an embedded line terminator

HighCVSS 8.7 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 34/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.57% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: node-xmldom (Debian:14) 0.9.12-1; @xmldom/xmldom (npm) 0.9.12.

Low priority for now. Upgrade to node-xmldom (Debian:14) 0.9.12-1; @xmldom/xmldom (npm) 0.9.12 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.10 until 0.9.12, the requireWellFormed: true serializer validates DocumentType.publicId and DocumentType.systemId with PubidLiteral_match and SystemLiteral_match expressions produced by reg() in lib/grammar.js, which inherit the multiline flag. A complete valid literal on the first line can therefore satisfy the matcher while U+000A, U+000D, U+2028, or U+2029 and breakout markup remain in the emitted <!DOCTYPE ...> declaration. This bypasses the strict-serialization mitigation for the earlier DocumentType injection advisory; creation and direct property assignment remain unvalidated by design. This issue is fixed in @xmldom/xmldom version 0.9.12.

Published
Sep 1, 2026
Updated
Sep 8, 2026
EPSS
0.5% · 47th percentile

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
8.7
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-83618

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • @xmldom xmldom

    • >= 0.9.10, < 0.9.12affected

  • xmldom xmldom

    • >= 0.9.10, < 0.9.12affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12node-xmldomfrom 0—
Debian:14node-xmldombefore 0.9.12-10.9.12-1
npm@xmldom/xmldomfrom 0.9.10 · before 0.9.120.9.12

Same product

xmldom: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-83619xmldom: End-tag Whitespace-Trim Regex ReDoS — quadratic backtracking in the 0.8.x end-tag parser
    34Monitor
  • CVE-2026-83617xmldom: requireWellFormed element/attribute name validation is bypassable via an embedded line terminator
    34Monitor
  • CVE-2026-83616xmldom: Processing Instruction Target Injection Bypasses requireWellFormed
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-83613Sep 1, 2026 · xmldom: Quadratic-time attribute deduplication
    34Monitor
  • ← EarlierCVE-2026-83614Sep 1, 2026 · xmldom: Quadratic-time parsing via the malformed-input recovery path — `parseElementStartPart` re-scan and `normalize()` adjacent-text…
    34Monitor
  • ← EarlierCVE-2026-83615Sep 1, 2026 · xmldom: Quadratic-memory consumption
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:node-xmldom0.9.12-1 · Debian:14Package registry (OSV)
npm:@xmldom/xmldom0.9.12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-836050 days apartxmldom: Attribute name injection via setAttribute() bypasses requireWellFormed
    34Monitor
  • CVE-2026-836070 days apartxmldom: Element name injection via createElement() bypasses requireWellFormed
    34Monitor
  • CVE-2026-836080 days apartxmldom: DocType `name` Injection Bypasses requireWellFormed
    34Monitor
  • CVE-2026-836090 days apartxmldom: Creation-time XML Name/QName validation is bypassable via an embedded line terminator, allowing injection on the default serialization path
    34Monitor
  • CVE-2026-836160 days apartxmldom: Processing Instruction Target Injection Bypasses requireWellFormed
    34Monitor
  • CVE-2026-836170 days apartxmldom: requireWellFormed element/attribute name validation is bypassable via an embedded line terminator
    34Monitor

Not on record for this CVE: researcher credit · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-91 · XML Injection (aka Blind XPath Injection)

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records