Fix CVE-2026-39821 and other advisories for v0.49.1 - #3209
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Google Cloud Marketplace flagged our published images for CVE-2026-39821 (GO-2026-5026), a Punycode validation flaw in golang.org/x/net/idna where ToASCII/ToUnicode accept an encoded label that decodes to an ASCII-only one, letting it slip past a hostname privilege check. The x/net module was already on v0.56.0, which carries the fix, so this looked like a false positive at first. It isn't: idna is also vendored into the standard library, and v0.49.0 was built with go1.25.11. govulncheck on the published binary still reports GO-2026-5026 reachable through net/http. The stdlib fix landed in go1.25.13, so raise the go directive to require it -- CI resolves go-version '~1.25' to the latest patch anyway, but nothing was stopping an older toolchain from producing a vulnerable build. That clears seven further stdlib advisories that came along for the ride. containerd v1.7.33 is a patch bump and clears two more. Deliberately left alone: cilium/ebpf, grpc and prometheus all need minor-version jumps into core profiling paths, which is not what a security patch release is for. govulncheck on the resulting binary: 21 findings down to 11, none of them in the standard library, and GO-2026-5026 gone.
brancz
approved these changes
Sep 7, 2026
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Google Cloud Marketplace flagged our published images for CVE-2026-39821, with a resubmit deadline of 2026-09-11. This looks like a false positive at first, since
x/netis already on v0.56.0 which carries the fix, butidnais also vendored into the standard library and v0.49.0 was built with go1.25.11. govulncheck on the published binary still reports it reachable throughnet/http. The stdlib fix is in go1.25.13, so thegodirective now requires it.Kept deliberately small for a patch release. containerd is a patch bump and clears two more advisories, however cilium/ebpf, grpc and prometheus would all need minor version jumps into core profiling paths, so those stay for a regular release. govulncheck goes from 21 findings to 11, with nothing left in the standard library.