CVE-2021-21366

unknown

Published 2021-03-12 · Modified 2026-03-13

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CVSS v3

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

CVSS v4 NEW

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not yet in upstream

VIR risk

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Description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. xmldom versions 0.4.0 and older do not correctly preserve system identifiers, FPIs or namespaces when repeatedly parsing and serializing maliciously crafted documents. This may lead to unexpected syntactic changes during XML processing in some downstream applications. This is fixed in version 0.5.0. As a workaround downstream applications can validate the input and reject the maliciously crafted documents.

Predictions

Exploit likelihood

30%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

OS	Version	Status	Fixed in
debian	bookworm	fixed	`0.5.0-1`
debian	bullseye	fixed	`0.5.0-1`
debian	forky	fixed	`0.5.0-1`
debian	sid	fixed	`0.5.0-1`
debian	trixie	fixed	`0.5.0-1`

Package impact

Ecosystem	Package	Vulnerable	Fixed
npm	xmldom	`<0.5.0`	`0.5.0`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.