net/sched: cls_flow: fix NULL pointer dereference on shared blocks
Summary
| CVE | CVE-2026-31422 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-13 14:16:11 UTC |
| Updated | 2026-04-18 09:16:32 UTC |
| Description | 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) [...] ======================================================================= |
Risk And Classification
EPSS: 0.000240000 probability, percentile 0.066100000 (date 2026-04-18)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db 57f94ac7e953eece5ed4819605a18f3cdfc63dcc git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db 942813276edeb1741fa5b0a73471beb4e495fa08 git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db cc707a4fd4c3b6ab2722e06bc359aa010e13d408 git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db 4a09f72007201c9f667dc47f64517ec23eea65e5 git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db 9bf5fc36a43f7b8b5507c96e74fb81f1e8b4957e git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db a208c3e1232997e9317887294c20008dfcb75449 git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db 415ea0c973c754b9f375225807810eb9045f4293 git | Not specified |
| CNA | Linux | Linux | affected 1abf272022cf1d18469405f47b4ec49c6a3125db 1a280dd4bd1d616a01d6ffe0de284c907b555504 git | Not specified |
| CNA | Linux | Linux | affected 4.15 | Not specified |
| CNA | Linux | Linux | unaffected 4.15 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.253 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.203 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.168 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.134 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.81 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.22 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.19.12 6.19.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/4a09f72007201c9f667dc47f64517ec23eea65e5 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/9bf5fc36a43f7b8b5507c96e74fb81f1e8b4957e | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/cc707a4fd4c3b6ab2722e06bc359aa010e13d408 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/942813276edeb1741fa5b0a73471beb4e495fa08 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/1a280dd4bd1d616a01d6ffe0de284c907b555504 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/57f94ac7e953eece5ed4819605a18f3cdfc63dcc | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/415ea0c973c754b9f375225807810eb9045f4293 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a208c3e1232997e9317887294c20008dfcb75449 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.