ammonia is a Rust library for repairing and securing untrusted HTML. Prior to 3.3.2, 4.0.2, and 4.1.3, applications that explicitly allow the math tag, annotation-xml, and at least one raw-text HTML element while disallowing the encoding attribute can permit mutation cross-site scripting. ammonia does not correctly implement annotation-xml's encoding-dependent MathML integration-point behavior after attribute filtering removes encoding, so the sanitizer validates a descendant under one namespace interpretation while the browser reparses the output under another. An attacker can use that namespace transition and an allowed raw-text HTML element to execute JavaScript when a user renders the sanitized output. The required tags are not enabled by default, so applications that do not explicitly allow them are not affected. This issue is fixed in versions 3.3.2, 4.0.2, and 4.1.3.
CVE-2026-63430
“—” beside the score: it is equal to the CVSS score beside it.
This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (46th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-102241 (ENISA EUVD) · GHSA-9jh8-v38h-cvhr (GitHub Security Advisories)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 6.3
- EG Score
- 6.3MEDIUMmedium confidence
- EG Risk
- 59EG Risk 59/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity63% × 45%Impact severity (EG Severity): CVSS 6.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.6%
- EPSS %ILE
- 46th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (6.3): severity, escalated by confirmed exploitation. This CVE's 6.3 is its impact severity (EG Severity), not escalated.
- EG Severity
- 6.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 15, 2026
Last Modified
October 16, 2026
Advisory Details (10)
Auto-updated Oct 15, 20264.1.3
Patch available: rust-ammonia/ammonia v4.1.3
https://github.com/rust-ammonia/ammonia/releases/tag/v4.1.34.0.2
Patch available: rust-ammonia/ammonia v4.0.2
https://github.com/rust-ammonia/ammonia/releases/tag/v4.0.23.3.2
Patch available: rust-ammonia/ammonia v3.3.2
https://github.com/rust-ammonia/ammonia/releases/tag/v3.3.2commit b51bf4f9749e (rust-ammonia/ammonia)
Patch available: rust-ammonia/ammonia v4.1.3 (contains commit b51bf4f9749e)
https://github.com/rust-ammonia/ammonia/commit/b51bf4f9749ed3cd518330105f20a2c39c9ee274commit 7ac3fd314523 (rust-ammonia/ammonia)
Patch available: rust-ammonia/ammonia v4.0.2 (contains commit 7ac3fd314523)
https://github.com/rust-ammonia/ammonia/commit/7ac3fd3145236f28857eeecbadb544c8659cba31commit 004bf2cee428 (rust-ammonia/ammonia)
Patch available: rust-ammonia/ammonia v3.3.2 (contains commit 004bf2cee428)
https://github.com/rust-ammonia/ammonia/commit/004bf2cee4288f74a6ee619d589e3e90c24c09caRelease 4.1.3 with security fix
Patch available: rust-ammonia/ammonia v4.1.3 (PR #245 merged 2026-06-30)
https://github.com/rust-ammonia/ammonia/pull/245Release 4.0.2 with security fix
Patch available: rust-ammonia/ammonia v4.0.2 (PR #244 merged 2026-06-30)
https://github.com/rust-ammonia/ammonia/pull/244Release 3.3.2 with security fix
Patch available: rust-ammonia/ammonia v3.3.2 (PR #243 merged 2026-06-30)
https://github.com/rust-ammonia/ammonia/pull/243mXSS in ammonia via MathML `annotation-xml` encoding strip · Advisory · rust-ammonia/ammonia · GitHub
https://github.com/rust-ammonia/ammonia/security/advisories/GHSA-9jh8-v38h-cvhrVendor Advisories for CVE-2026-63430(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
crates.io(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| ammonia | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 24× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-29 16:41 UTCEG score recompute
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-25 14:13 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-22 19:49 UTCEG score recompute
- 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-18 03:23 UTCEG score recompute
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-15 21:26 UTCEG score recompute
- 2026-10-15 20:31 UTCEG score recompute
- 2026-10-15 19:35 UTCEG score recompute
- 2026-10-15 18:24 UTCEG score recomputeFirst assessed: 6.3 MEDIUM
- 2026-10-15 18:22 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
3 showncrates.io:ammonia
Frequently asked(5)
What is CVE-2026-63430?
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Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-63430
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