CVE-2026-64306: crypto: drbg - Fix returning success on failure in CTR_DRBG

From: Greg Kroah-Hartman <[email protected]>

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

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

crypto: drbg - Fix returning success on failure in CTR_DRBG

drbg_ctr_generate() sometimes returns success when it fails, leaving the
output buffer uninitialized.  Fix it.

The Linux kernel CVE team has assigned CVE-2026-64306 to this issue.


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

	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 5.10.261 with commit 074db6db03a0aaa78f05ca9d4838053713796665
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 5.15.212 with commit 7b03312491f9fe6ba4d60c4023e7e61d2d1fed96
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 6.1.178 with commit 75597e8774f319152744d24e0683d9393540a951
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 6.6.145 with commit cc42fb40171c249bb859071d81b4eb007398a0bc
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 6.12.96 with commit bbbac12083eff489b35d848332f0dff311131344
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 6.18.39 with commit 23b8b188cb32e5531d0f8d3af9506f8959cb369e
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 7.1.4 with commit a9e886f73dd717027028bb7e3bbca93601ecdfc7
	Issue introduced in 4.1 with commit cde001e4c3c3625c60b68a83eb1f1c2572dee07a and fixed in 7.2-rc1 with commit 39a31ad9e2a5ed7e9c9c6f711dca96c8c8f5f26b
	Issue introduced in 3.12.44 with commit f60b0fa8bbddde66f1d197be07120264b555c84a

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-2026-64306
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:
	crypto/drbg.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/074db6db03a0aaa78f05ca9d4838053713796665
	https://git.kernel.org/stable/c/7b03312491f9fe6ba4d60c4023e7e61d2d1fed96
	https://git.kernel.org/stable/c/75597e8774f319152744d24e0683d9393540a951
	https://git.kernel.org/stable/c/cc42fb40171c249bb859071d81b4eb007398a0bc
	https://git.kernel.org/stable/c/bbbac12083eff489b35d848332f0dff311131344
	https://git.kernel.org/stable/c/23b8b188cb32e5531d0f8d3af9506f8959cb369e
	https://git.kernel.org/stable/c/a9e886f73dd717027028bb7e3bbca93601ecdfc7
	https://git.kernel.org/stable/c/39a31ad9e2a5ed7e9c9c6f711dca96c8c8f5f26b