Unknown severity · Source severity not reportedCVE-2026-78661

Avoid quadratic complexity when coalescing text nodes in html in golang.org/x/netCVE-2026-78661

Answer in brief

CVE-2026-78661 records a Unknown severity vulnerability in Avoid quadratic complexity when coalescing text nodes in html in golang.org/x/net. The current sources do not mark it as known exploited. The current feed maps golang.org/x/net (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 27, 2026Updated Oct 27, 2026Source checked Oct 27, 2026First seen by HOL Oct 27, 2026Material review Oct 27, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps golang.org/x/net (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
golang.org/x/netgo	>=0 <0.62.0	0.62.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for golang.org/x/net.
Review the reported fix. Update golang.org/x/net to 0.62.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 27, 2026
Evidence: source:osv:source_dates:source-dates:record
Source modified
Oct 27, 2026
Evidence: source:osv:source_dates:source-dates:record
First seen by HOL
Oct 27, 2026

Sources and claim methodology

Upstream source description

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>") 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.

Quoted source text, attributed separately from HOL analysis.