8.7

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

Deferred
AliasesUBUNTU-CVE-2026-83618DEBIAN-CVE-2026-83618GHSA-vr34-hp96-76pp
Published 01-09-2026Last modified 04-09-2026

Vulnerability summary

CVE-2026-83618 is a high (CVSS 8.7) XML Injection vulnerability in xmldom. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 47.2% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 8.7 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.57%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 01-09-2026
    PublishedVulnerability first disclosed.
  2. 04-09-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.57%

Chance of exploitation in the next 30 days

Percentile

47%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.57% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

@xmldom1 product
  • xmldom≥ 0.9.10, < 0.9.12
Debian1 product
  • node-xmldomAll versions (No fix recorded) | < 0.9.12-1
Ubuntu1 product
  • node-xmldomAll versions (No fix recorded)
Xmldom1 product

4 vendors · 4 products

References

9 links