CVE-2026-78661

UNRATEDCVSS · not yet scoredTrending — 6 sources updated this week

Also known asEUVD-2026-111399 (ENISA EUVD) · GHSA-75pg-wvh3-34jr (GitHub Security Advisories)Source: ENISA EUVD

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EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS v2: —Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

When coalescing adjacent text nodes in addText and fosterParent, appending to an existing TextNode's Data via string concatenation (n.Data += text) reallocated and copied the accumulated string on every token. Inputs containing many short text runs separated by ignored end tags (such as "a") caused O(n^2) allocations and byte copies. Accumulate coalesced text in per-node byte slices during parsing and materialize Data strings once at the end of parse.

CVSS v3
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EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
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EPSS PROB
0.2%
EPSS %ILE
8th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

EG Severity
Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS. 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
No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the BOD 26-04 block below.

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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 27, 2026

Last Modified

October 28, 2026

References (4)

Vendor Advisories for CVE-2026-78661(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 11× in last 7d / 11× 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.

  1. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  2. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  4. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  5. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  6. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  7. 2026-10-28 15:27 UTCGHSA enrichmentGHSA-75pg-wvh3-34jr
  8. 2026-10-27 22:25 UTCNVD update
  9. 2026-10-27 22:01 UTCENISA EUVD ID recordedEUVD-2026-111399 · Source: ENISA EUVD
  10. 2026-10-27 21:48 UTCEG score recompute
  11. 2026-10-27 21:45 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-78661?
CVE-2026-78661 is a vulnerability whose severity is not yet rated; its CVE record was published on October 27, 2026. When coalescing adjacent text nodes in addText and fosterParent, appending to an existing TextNode's Data via string concatenation (n.Data += text) reallocated and copied the accumulated string on every token. Inputs containing many short text runs separated by ignored end tags (such as "a</x>")…
When was the CVE record for CVE-2026-78661 published?
The CVE record for CVE-2026-78661 was published on October 27, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 28, 2026; the record at its source may have been updated since.
Is CVE-2026-78661 actively exploited?
CVE-2026-78661 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
How do I remediate CVE-2026-78661?
A fix for CVE-2026-78661 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-78661 are linked in the Vendor Advisories panel on this page.

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