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| author | Roland Shoemaker <bracewell@google.com> | 2026-01-09 11:12:01 -0800 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2026-03-05 16:12:49 -0800 |
| commit | 994692847a2cd3efd319f0cb61a07c0012c8a4ff (patch) | |
| tree | 6420c79163711856095efff03655727438064651 /src/html/template/context.go | |
| parent | 65c7d7a9fb3a9d1fbf1e702a211b8cc3a7bedb53 (diff) | |
| download | go-994692847a2cd3efd319f0cb61a07c0012c8a4ff.tar.xz | |
[release-branch.go1.26] html/template: properly escape URLs in meta content attributes
The meta tag can include a content attribute that contains URLs, which
we currently don't escape if they are inserted via a template action.
This can plausibly lead to XSS vulnerabilities if untrusted data is
inserted there, the http-equiv attribute is set to "refresh", and the
content attribute contains an action like `url={{.}}`.
Track whether we are inside of a meta element, if we are inside of a
content attribute, _and_ if the content attribute contains "url=". If
all of those are true, then we will apply the same URL escaping that we
use elsewhere.
Also add a new GODEBUG, htmlmetacontenturlescape, to allow disabling this
escaping for cases where this behavior is considered safe. The behavior
can be disabled by setting htmlmetacontenturlescape=0.
Updates #77954
Fixes #77972
Fixes CVE-2026-27142
Change-Id: I9bbca263be9894688e6ef1e9a8f8d2f4304f5873
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/3360
Reviewed-by: Neal Patel <nealpatel@google.com>
Reviewed-by: Nicholas Husin <husin@google.com>
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/3643
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/752081
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Bypass: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Diffstat (limited to 'src/html/template/context.go')
| -rw-r--r-- | src/html/template/context.go | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/html/template/context.go b/src/html/template/context.go index b78f0f7325..8b3af2feab 100644 --- a/src/html/template/context.go +++ b/src/html/template/context.go @@ -156,6 +156,10 @@ const ( // stateError is an infectious error state outside any valid // HTML/CSS/JS construct. stateError + // stateMetaContent occurs inside a HTML meta element content attribute. + stateMetaContent + // stateMetaContentURL occurs inside a "url=" tag in a HTML meta element content attribute. + stateMetaContentURL // stateDead marks unreachable code after a {{break}} or {{continue}}. stateDead ) @@ -267,6 +271,8 @@ const ( elementTextarea // elementTitle corresponds to the RCDATA <title> element. elementTitle + // elementMeta corresponds to the HTML <meta> element. + elementMeta ) //go:generate stringer -type attr @@ -288,4 +294,6 @@ const ( attrURL // attrSrcset corresponds to a srcset attribute. attrSrcset + // attrMetaContent corresponds to the content attribute in meta HTML element. + attrMetaContent ) |