CVE-2026-56865

NameCVE-2026-56865
DescriptionA 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
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1144340, 1144341, 1144342

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
golang-1.15 (PTS)bullseye1.15.15-1~deb11u4vulnerable
golang-1.19 (PTS)bookworm1.19.8-2vulnerable
golang-1.24 (PTS)trixie1.24.4-1vulnerable
golang-1.25 (PTS)forky, sid1.25.12-1vulnerable
golang-1.26 (PTS)forky, sid1.26.5-1vulnerable
golang-1.27 (PTS)forky, sid1.27~rc2-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
golang-1.15source(unstable)(unfixed)
golang-1.19source(unstable)(unfixed)
golang-1.24source(unstable)(unfixed)
golang-1.25source(unstable)(unfixed)1144342
golang-1.26source(unstable)(unfixed)1144341
golang-1.27source(unstable)(unfixed)1144340

Notes

[trixie] - golang-1.24 <no-dsa> (Minor issue)
https://github.com/golang/go/issues/80744
Fixed by: https://github.com/golang/go/commit/b0365c1777662ae45534c0e728a12a8b19874759 (go1.27rc3)
Fixed by: https://github.com/golang/go/commit/115eb476aaca4531374c42e19e6f199265c2e25e (go1.26.6)
Fixed by: https://github.com/golang/go/commit/b0b8c97d1386bb3eb978e727ed0b1df8e14df569 (go1.25.13)

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