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CVE-2026-31422

net/sched: cls_flow: fix NULL pointer dereference on shared blocks PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_flow: fix NULL pointer dereference on shared blocks flow_change() calls tcf_block_q() and dereferences q->handle to derive a default baseclass. Shared blocks leave block->q NULL, causing a NULL deref when a flow filter without a fully qualified baseclass is created on a shared block. Check tcf_block_shared() before accessing block->q and return -EINVAL for shared blocks. This avoids the null-deref shown below: ======================================================================= KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f] RIP: 0010:flow_change (net/sched/cls_flow.c:508) Call Trace: tc_new_tfilter (net/sched/cls_api.c:2432) rtnetlink_rcv_msg (net/core/rtnetlink.c:6980) [...] =======================================================================

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 1abf272022cf1d18469405f47b4ec49c6a3125db before 57f94ac7e953eece5ed4819605a18f3cdfc63dcc; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before 942813276edeb1741fa5b0a73471beb4e495fa08; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before cc707a4fd4c3b6ab2722e06bc359aa010e13d408; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before 4a09f72007201c9f667dc47f64517ec23eea65e5; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before 9bf5fc36a43f7b8b5507c96e74fb81f1e8b4957e; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before a208c3e1232997e9317887294c20008dfcb75449; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before 415ea0c973c754b9f375225807810eb9045f4293; affected 1abf272022cf1d18469405f47b4ec49c6a3125db before 1a280dd4bd1d616a01d6ffe0de284c907b555504
Linux / Linuxaffected 4.15; unaffected 0 before 4.15; unaffected 5.10.253 through 5.10.*; unaffected 5.15.203 through 5.15.*; unaffected 6.1.168 through 6.1.*; unaffected 6.6.134 through 6.6.*; unaffected 6.12.81 through 6.12.*; unaffected 6.18.22 through 6.18.*; unaffected 6.19.12 through 6.19.*; unaffected 7.0 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

siemens-SADP

No English description supplied.