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CVE-2026-72296
net: ife: require ETH_HLEN to be pullable in ife_decode()
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem net/ife. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-72296 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
ife decode may return after making only the outer IFE header and metadata pullable. The caller then passes the decapsulated packet to eth_type_trans(), which expects the inner Ethernet header to be accessible from the linear data area. With a malformed IFE frame, the inner Ethernet header may still be shorter than ETH_HLEN in the linear area, which can lead to a crash in the original code. Fix this by extending the pull check in ife_decode() so that the inner Ethernet header is also guaranteed to be pullable before returning.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/ife/ife.c
- What this is
- IFE PROTOCOLMAINTAINERS section matched on net/ife
- Kernel module
- ife
Check it on the machine
grep -w CONFIG_NET_IFE /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w ifePrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switch
- CONFIG_NET_IFE
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 9.1 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.73%, higher than 53.5% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/ife
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.6 | 5.10.261 | 70013f9163be |
| 4.6 | 5.15.212 | be272e159dfe |
| 4.6 | 6.1.178 | 8c8818e52fdd |
| 4.6 | 6.6.145 | 9433578bff9c |
| 4.6 | 6.12.97 | 1cb42ec10294 |
| 4.6 | 6.18.40 | 5526d1997aea |
| 4.6 | 7.1.5 | b69ad768cd4a |
| 4.6 | 7.2 | 9406f6012b73 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:NAttack vector, network
- The flaw is hit on the ingress packet receive path (__netif_receive_skb_core→sch_handle_ingress→tc_run→tcf_ife_act→ife_decode) when a remote peer sends a malformed IFE-encapsulated Ethernet frame to a netdev with clsact/ingress IFE decode, as in SDN/NFV/ForCES edge nodes.
- AC:LAttack complexity, low
- Once ingress IFE decode is present, the attacker fully controls the crafted frame (metalen, metadata size, and skb layout) to leave the inner Ethernet header non-linear or shorter than ETH_HLEN, deterministically reaching eth_type_trans() without races or uncontrollable memory layout.
- PR:NPrivileges required, none
- Remote exploitation needs no credentials or capabilities on the victim—only delivery of a malformed frame to an interface already configured with IFE decode; CAP_NET_ADMIN is an operator deployment prerequisite, not attacker privilege (same model as pre-configured nftables offload bugs).
- UI:NUser interaction, none
- No victim user action is required beyond normal network delivery of attacker-crafted IFE traffic; exploitation does not depend on mounting, opening files, or administrator interaction at attack time.
- S:UScope, unchanged
- Impact is confined to kernel packet-processing memory within the same kernel security authority; this is not a VM escape, IOMMU bypass, or cross-namespace scope change.
- C:HConfidentiality impact, high
- eth_type_trans() reads the inner struct ethhdr (h_dest/h_proto) via eth_skb_pull_mac()/eth_skb_pkt_type() without ensuring ETH_HLEN bytes are linear, causing an out-of-bounds kernel read that can disclose adjacent skb/page memory beyond a few bytes.
- I:NIntegrity impact, none
- The defect is a missing pskb_may_pull() bounds check leading to out-of-bounds reads and crash; there is no write, UAF, or demonstrated arbitrary modification or control-flow hijack primitive.
- A:HAvailability impact, high
- The fix commit states malformed IFE frames can crash the kernel; accessing a non-linear or undersized inner Ethernet header in eth_type_trans() can trigger KASAN faults, oops, or panic on the softirq receive path.