In the Linux kernel, the following vulnerability has been resolved:
clsact: Fix use-after-free in init/destroy rollback asymmetry
Fix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry.
The latter is achieved by first fully initializing a clsact instance, and
then in a second step having a replacement failure for the new clsact qdisc
instance. clsact_init() initializes ingress first and then takes care of the
egress part. This can fail midway, for example, via tcf_block_get_ext(). Upon
failure, the kernel will trigger the clsact_destroy() callback.
Commit 1cb6f0bae504 ("bpf: Fix too early release of tcx_entry") details the
way how the transition is happening. If tcf_block_get_ext on the q->ingress_block
ends up failing, we took the tcx_miniq_inc reference count on the ingress
side, but not yet on the egress side. clsact_destroy() tests whether the
{ingress,egress}_entry was non-NULL. However, even in midway failure on the
replacement, both are in fact non-NULL with a valid egress_entry from the
previous clsact instance.
What we really need to test for is whether the qdisc instance-specific ingress
or egress side previously got initialized. This adds a small helper for checking
the miniq initialization called mini_qdisc_pair_inited, and utilizes that upon
clsact_destroy() in order to fix the use-after-free scenario. Convert the
ingress_destroy() side as well so both are consistent to each other.
References
Configurations
Configuration 1 (hide)
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History
24 Apr 2026, 15:22
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.10:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
|
| First Time |
Linux
Linux linux Kernel |
|
| CWE | CWE-416 | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| References | () https://git.kernel.org/stable/c/0509b762bc5e8ea7b8391130730c6d8502fc6e69 - Patch | |
| References | () https://git.kernel.org/stable/c/37bef86e5428d59f70a4da82b80f9a8f252fecbe - Patch | |
| References | () https://git.kernel.org/stable/c/4c9af67f99aa3e51b522c54968ab3ac8272be41c - Patch | |
| References | () https://git.kernel.org/stable/c/a0671125d4f55e1e98d9bde8a0b671941987e208 - Patch | |
| References | () https://git.kernel.org/stable/c/a73d95b57bf9faebdfed591bcb7ed9292062a84c - Patch |
02 Apr 2026, 12:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-02 12:16
Updated : 2026-04-27 14:16
NVD link : CVE-2026-23413
Mitre link : CVE-2026-23413
CVE.ORG link : CVE-2026-23413
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free
