GO-2026-6860 CVE-2026-78661
Avoid quadratic complexity when coalescing text nodes in html in golang.org/x/net
- Severity
- Not rated yet
- No source has published a CVSS score yet
- Exploit chance (EPSS)
- 0.18%
- Chance of exploitation in the next 30 days. Higher than 8.07% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- —
- Not classified
- Fix
0.62.0- Upgrade golang.org/x/net to this version or later
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.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| golang.org/x/net | < 0.62.0 |
0.62.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
golang.org/x/net Go → 0.62.0
- go
go get golang.org/x/net@v0.62.0 && go mod tidy
References
Fixes and patches
Issue reports
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-4374-p667-p6c8 HTTP/2 rapid reset can cause excessive work in net/http | High Known exploited | Also affects golang.org/x/net |
| GHSA-qppj-fm5r-hxr3 HTTP/2 Stream Cancellation Attack | Medium Known exploited | Also affects golang.org/x/net |
| GO-2026-6866 Check all ancestor namespace transitions when rendering raw text in html in golang.org/x/net | Not rated yet | Also affects golang.org/x/net |
| GO-2026-6617 HTTP/2 server crash due to HPACK encoder race in net/http | High | Also affects golang.org/x/net |
| GO-2026-6612 Double flow control refund on HTTP/2 server streams in net/http | Critical | Also affects golang.org/x/net |
| GO-2026-6611 Excessive CPU consumption from repeated initial window changes in net/http | High | Also affects golang.org/x/net |
| GO-2026-6610 HTTP/2 transport accepts malformed framing-related headers in net/http | High | Also affects golang.org/x/net |
| GO-2026-6603 HTTP/2 server memory exhaustion due to Trailer headers in net/http | High | Also affects golang.org/x/net |
Credits: Markus Magnuson
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