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Review reviewHigh

CVE-2023-54193

Linux

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: remove block_cb from driver_list before freeing Error handler of tcf_block_bind() frees the whole bo->cb_list on error. However, by that time the flow_block_cb instances are already in the driver list because driver ndo_setup_tc() callback is called before that up the call chain in tcf_block_offload_cmd(). This leaves dangling pointers to freed objects in the list and causes use-after-free[0]. Fix it by also removing flow_block_cb instances from driver_list before deallocating them. [0]: [ 279.868433] ==...

CVSS
7.8
EPSS
0.14%
3.81% percentile
CISA KEV
Not listed
Published
2025.12.30
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.14%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: remove block_cb from driver_list before freeing Error handler of tcf_block_bind() frees the whole bo->cb_list on error. However, by that time the flow_block_cb instances are already in the driver list because driver ndo_setup_tc() callback is called before that up the call chain in tcf_block_offload_cmd(). This leaves dangling pointers to freed objects in the list and causes use-after-free[0]. Fix it by also removing flow_block_cb instances from driver_list before deallocating them. [0]: [ 279.868433] ==...

Affected product and versions

Product
Linux
Affected versions
>= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < cc5fe387c6294d0471cb7ed064efac97fac65ccc, >= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < 7311c8be3755611bf6edea4dfbeb190b4bdd489f, >= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < cb145932fcf6814e7e95e467eb70e7849a845ae9, >= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < 55866fe3fded3ce94ac3fc1bb3dfce654282f483, >= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < 26aec72429a05e917d574eca0efc5306c63a8862, >= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < 7b7a74ed303d532fb73ae4b1697f16a0fea89cd0, >= 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 < da94a7781fc3c92e7df7832bc2746f4d39bc624e, >= 5.3
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available