From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89906: LoongArch: BPF: Refactor jump offset calculation in tail call
Date: Wed, 16 Sep 2026 11:30:36 +0100 [thread overview]
Message-ID: <2026091640-CVE-2026-89906-17db@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
LoongArch: BPF: Refactor jump offset calculation in tail call
The old macro-based jmp_offset calculation derives the jump distance
from a stale prior-pass code stride, which can lead to wrong branch
offsets and soft lockups under extra JIT passes.
Fix this by calculating the offset directly on the absolute target:
"ctx->offset[insn + 1] - ctx->idx".
To avoid a false 16-bit range check abort during size estimation, add
a "ctx->image == NULL" guard to inject a safe dummy offset.
The Linux kernel CVE team has assigned CVE-2026-89906 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.17 with commit cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 and fixed in 6.18.51 with commit 882b8912b7e92341fdb115ba0e2e5142a28684ff
Issue introduced in 6.17 with commit cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 and fixed in 7.2.5 with commit 96f44d493c280ea161569c43d7ed0f3b0815803a
Issue introduced in 6.17 with commit cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 and fixed in 7.3-rc1 with commit 37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8
Issue introduced in 6.1.149 with commit 1a782fa32e644aa9fbae6c8488f3e61221ac96e1
Issue introduced in 6.6.103 with commit 17c010fe45def335fe03a0718935416b04c7f349
Issue introduced in 6.12.43 with commit f83d469e16bb1f75991ca67c56786fb2aaa42bea
Issue introduced in 6.15.11 with commit f2b5e50cc04d7a049b385bc1c93b9cbf5f10c94f
Issue introduced in 6.16.2 with commit 9262e3e04621558e875eb5afb5e726b648cd5949
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-2026-89906
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:
arch/loongarch/net/bpf_jit.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/882b8912b7e92341fdb115ba0e2e5142a28684ff
https://git.kernel.org/stable/c/96f44d493c280ea161569c43d7ed0f3b0815803a
https://git.kernel.org/stable/c/37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8
reply other threads:[~2026-09-16 10:38 UTC|newest]
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