[security] Go 1.26.2 and Go 1.25.9 are released

[anno...@golang.org]

Hello gophers,

We have just released Go versions 1.26.2 and 1.25.9, minor point releases.

These releases include 10 security fixes following the security policy:

• os: Root.Chmod can follow symlinks out of the root on Linux

  On Linux, if the target of Root.Chmod is replaced with a symlink while
  the chmod operation is in progress, Chmod could operate on the target
  of the symlink, even when the target lies outside the root.

  The Linux fchmodat syscall silently ignores the AT_SYMLINK_NOFOLLOW flag,
  which Root.Chmod uses to avoid symlink traversal. Root.Chmod checks its
  target before acting and returns an error if the target is a symlink
  lying outside the root, so the impact is limited to cases where the
  target is replaced with a symlink between the check and operation.

  On Linux, Root.Chmod now uses the fchmodat2 syscall when available, and
  an workaround using /proc/self/fd otherwise.

  Thanks to Uuganbayar Lkhamsuren for reporting this issue.

  This is CVE-2026-32282 and Go issue https://go.dev/issue/78293.

• html/template: JS template literal context incorrectly tracked

  Context was not properly tracked across template branches for JS template
  literals, leading to possibly incorrect escaping of content when branches were
  used.

  Additionally template actions within JS template literals did not properly track
  the brace depth, leading to incorrect escaping being applied.

  These issues could cause actions within JS template literals to be incorrectly
  or improperly escaped, leading to XSS vulnerabilities.

  This only affects templates that use template actions within JS template literals.

  This is CVE-2026-32289 and Go issue https://go.dev/issue/78331.

• crypto/x509: excluded DNS constraints not properly applied to wildcard domains

  When verifying a certificate chain containing excluded DNS constraints, these
  constraints are not correctly applied to wildcard DNS SANs which use a different
  case than the constraint.

  For example, if a certificate contains the DNS name "*.example.com" and the
  excluded DNS name "EXAMPLE.COM", the constraint will not be applied.

  This only affects validation of otherwise trusted certificate chains, issued by
  a root CA in the VerifyOptions.Roots CertPool, or in the system certificate
  pool.

  This issue only affects Go 1.26.

  Thank you to Riyas from Saintgits College of Engineering, k1rnt, @1seal for reporting this issue.

  This is CVE-2026-33810 and Go issue https://go.dev/issue/78332.

• cmd/compile: no-op interface conversion bypasses overlap checking

  Previously, the compiler failed to unwrap pointers contained within
  a no-op interface conversion leading to an incorrect determination
  of a non-overlapping move.

  To prevent unsafe move operations, the compiler will now unwrap all
  such conversions before considering a move non-overlapping.

  Thank you to Jakub Ciolek - https://ciolek.dev/ for reporting this issue.

  This is CVE-2026-27144 and Go issue https://go.dev/issue/78371.

• cmd/compile: possible memory corruption after bound check elimination

  Previously, slices and arrays accessed using induction variables
  were sometimes incorrectly proved in-bound. If the induction variable
  used for indexing were to overflow or underflow, it could allow access
  to memory beyond the scope of the original slice or array.

  To prevent this behavior, the compiler ensures that any mutated induction
  variable that overflows/underflows with respect to its loop condition
  is not used for bound check elimination.

  Thank you to Jakub Ciolek - https://ciolek.dev/ for reporting this issue.

  This is CVE-2026-27143 and Go issue https://go.dev/issue/78333.

• archive/tar: unbounded allocation when parsing old format GNU sparse map

  tar.Reader could allocate an unbounded amount of memory when reading
  a maliciously-crafted archive containing a large number of sparse
  regions encoded in the "old GNU sparse map" format.

  We now limit both the number of old GNU sparse map extension blocks,
  and the total number of sparse file entries, regardless of encoding.

  Thanks to Colin Walters (wal...@verbum.org) who initially reported this issue.
  Thanks also to Uuganbayar Lkhamsuren (https://github.com/uug4na) and Jakub Ciolek
  who additionally reported this issue.

  This is CVE-2026-32288 and Go issue https://go.dev/issue/78301.

• crypto/tls: multiple key update handshake messages can cause connection to deadlock

  If one side of the TLS connection sends multiple key update messages
  post-handshake in a single record, the connection can deadlock, causing
  uncontrolled consumption of resources. This can lead to a denial of service.

  This only affects TLS 1.3.

  Thank you to Jakub Ciolek - https://ciolek.dev/ for reporting this issue.

  This is CVE-2026-32283 and Go issue https://go.dev/issue/78334.

• cmd/go: trust layer bypass when using cgo and SWIG

  A well-crafted SWIG source file could take advantage
  of a file-naming convention used inside the trust
  boundary of the cgo compiler. Doing so could result
  in arbitrary code execution during build time.

  SWIG files are disallowed from using this convention.

  Thank you to Juho Forsén of Mattermost for reporting this issue.

  This is CVE-2026-27140 and Go issue https://go.dev/issue/78335.

• crypto/x509: unexpected work during chain building

  During chain building, the amount of work that is done is not correctly limited
  when a large number of intermediate certificates are passed in
  VerifyOptions.Intermediates, which can lead to a denial of service. This affects
  both direct users of crypto/x509 and users of crypto/tls.

  Thank you to Jakub Ciolek - https://ciolek.dev/ for reporting this issue.

  This is CVE-2026-32280 and Go issue https://go.dev/issue/78282.

• crypto/x509: inefficient policy validation

  Validating certificate chains which use policies is unexpectedly inefficient
  when certificates in the chain contain a very large number of policy mappings,
  possibly causing denial of service.

  This only affects validation of otherwise trusted certificate chains, issued by
  a root CA in the VerifyOptions.Roots CertPool, or in the system certificate
  pool.

  Thank you to Jakub Ciolek - https://ciolek.dev/ for reporting this issue.

  This is CVE-2026-32281 and Go issue https://go.dev/issue/78281.

View the release notes for more information:
https://go.dev/doc/devel/release#go1.26.2

You can download binary and source distributions from the Go website:
https://go.dev/dl/

To compile from source using a Git clone, update to the release with
git checkout go1.26.2 and build as usual.

Thanks to everyone who contributed to the releases.

Cheers,
David and Junyang for the Go team