CVE-2026-78661 Affecting runc-1.4 package, versions <1.4.3-r13
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CHAINGUARDLATEST-RUNC14-21788364
- published29 Oct 2026
- disclosed27 Oct 2026
Introduced: 27 Oct 2026
NewCVE-2026-78661 (opens in a new tab)How to fix?
Upgrade Chainguard runc-1.4 to version 1.4.3-r13 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream runc-1.4 package and not the runc-1.4 package as distributed by Chainguard.
See How to fix? for Chainguard relevant fixed versions and status.
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.