CVE-2026-78661
Avoid quadratic complexity when coalescing text nodes in html in golang.org/x/net
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| golang.org/x/net/html golang.org/x/net golang.org/x/net/html
https://pkg.go.dev |
≥ 0; < 0.62.0 (affected, semver)
Other versions: unaffected |
CNA: Go |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | ADP: CISA-ADP |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD: 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://go.dev/cl/849365CNA: Go
- https://go.dev/issue/82224CNA: Go
- https://groups.google.com/g/golang-announce/c/sqrs2vTx_XsCNA: Go
- https://pkg.go.dev/vuln/GO-2026-6860CNA: Go
- https://go.dev/cl/849365[email protected]
- https://go.dev/issue/82224[email protected]
- https://groups.google.com/g/golang-announce/c/sqrs2vTx_Xs[email protected]
- https://pkg.go.dev/vuln/GO-2026-6860[email protected]
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