CVE-2026-98778: binder: fix is_failure flag for superseded transaction cleanup

CVE-2026-98778: binder: fix is_failure flag for superseded transaction cleanup

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

binder: fix is_failure flag for superseded transaction cleanup

When a TF_UPDATE_TXN transaction supersedes a pending async transaction,
binder_release_entire_buffer() is called with is_failure=false. Since the
superseded transaction was never delivered, binder_apply_fd_fixups() was
never called and no fds were installed in the target process.

With is_failure=false, the BINDER_TYPE_FDA cleanup handler interprets
stale buffer contents as installed fd numbers and passes them to
binder_deferred_fd_close(), closing unrelated file descriptors.

Pass is_failure=true since the transaction was never delivered to the
target, matching the semantics of all other undelivered-transaction
cleanup paths.

The Linux kernel CVE team has assigned CVE-2026-98778 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.0 with commit 9864bb4801331daa48514face9d0f4861e4d485b and fixed in 6.12.113 with commit 60a9f7323ae7318a7cce0d387c318da24f1e8726
	Issue introduced in 6.0 with commit 9864bb4801331daa48514face9d0f4861e4d485b and fixed in 6.18.56 with commit 86cdcc87d4ba60aebf94ba3346b3c900c5cd79ff
	Issue introduced in 6.0 with commit 9864bb4801331daa48514face9d0f4861e4d485b and fixed in 7.2.10 with commit 1ab671b50714ad8e359cf37eb041d8044319ccdc
	Issue introduced in 6.0 with commit 9864bb4801331daa48514face9d0f4861e4d485b and fixed in 7.3-rc6 with commit 22c135635fdd9816c0ef140d6de7b2e4fdf73e89

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-98778
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/android/binder.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/60a9f7323ae7318a7cce0d387c318da24f1e8726
	https://git.kernel.org/stable/c/86cdcc87d4ba60aebf94ba3346b3c900c5cd79ff
	https://git.kernel.org/stable/c/1ab671b50714ad8e359cf37eb041d8044319ccdc
	https://git.kernel.org/stable/c/22c135635fdd9816c0ef140d6de7b2e4fdf73e89