Hello gophers, We have tagged version v0.40.0 of golang.org/x/mod in order to address the following security issues:
x/mod/sumdb/tlog: fix transparency log tile verification bypass A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy Thanks to Filippo Valsorda (Geomys) for reporting this issue. This is CVE-2026-56865 and Go issue https://go.dev/issue/80744. x/mod/sumdb: ignore unrelated, unauthenticated hashes in Lookup A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the transparency log. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy Thanks to mundur for reporting this issue. This is CVE-2026-56864 and Go issue https://go.dev/issue/80745. Cheers, Go Security team -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/golang-nuts/4d79e4be.EAAACRzdeLkAAAAAAAAAA-p9MGIAAYKKSQYAAAAAADE8OwBqfhzu%40mailjet.com.
