Bug 2451271 (CVE-2026-23378)

Summary:	CVE-2026-23378 kernel: net/sched: act_ife: Fix metalist update behavior
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel, specifically within the networking scheduler's Ingress Forwarding Engine (IFE) action. When an IFE action attempts to replace metadata, it incorrectly appends new metadata instead of replacing the old. This unbounded addition of metadata can lead to an out-of-bounds memory write during the encoding operation. An attacker, by manipulating network traffic, could potentially trigger a denial of service or achieve arbitrary code execution within the kernel.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-03-25 11:08:12 UTC

In the Linux kernel, the following vulnerability has been resolved:

net/sched: act_ife: Fix metalist update behavior

Whenever an ife action replace changes the metalist, instead of
replacing the old data on the metalist, the current ife code is appending
the new metadata. Aside from being innapropriate behavior, this may lead
to an unbounded addition of metadata to the metalist which might cause an
out of bounds error when running the encode op:

[  138.423369][    C1] ==================================================================
[  138.424317][    C1] BUG: KASAN: slab-out-of-bounds in ife_tlv_meta_encode (net/ife/ife.c:168)
[  138.424906][    C1] Write of size 4 at addr ffff8880077f4ffe by task ife_out_out_bou/255
[  138.425778][    C1] CPU: 1 UID: 0 PID: 255 Comm: ife_out_out_bou Not tainted 7.0.0-rc1-00169-gfbdfa8da05b6 #624 PREEMPT(full)
[  138.425795][    C1] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  138.425800][    C1] Call Trace:
[  138.425804][    C1]  <IRQ>
[  138.425808][    C1]  dump_stack_lvl (lib/dump_stack.c:122)
[  138.425828][    C1]  print_report (mm/kasan/report.c:379 mm/kasan/report.c:482)
[  138.425839][    C1]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[  138.425844][    C1]  ? __virt_addr_valid (./arch/x86/include/asm/preempt.h:95 (discriminator 1) ./include/linux/rcupdate.h:975 (discriminator 1) ./include/linux/mmzone.h:2207 (discriminator 1) arch/x86/mm/physaddr.c:54 (discriminator 1))
[  138.425853][    C1]  ? ife_tlv_meta_encode (net/ife/ife.c:168)
[  138.425859][    C1]  kasan_report (mm/kasan/report.c:221 mm/kasan/report.c:597)
[  138.425868][    C1]  ? ife_tlv_meta_encode (net/ife/ife.c:168)
[  138.425878][    C1]  kasan_check_range (mm/kasan/generic.c:186 (discriminator 1) mm/kasan/generic.c:200 (discriminator 1))
[  138.425884][    C1]  __asan_memset (mm/kasan/shadow.c:84 (discriminator 2))
[  138.425889][    C1]  ife_tlv_meta_encode (net/ife/ife.c:168)
[  138.425893][    C1]  ? ife_tlv_meta_encode (net/ife/ife.c:171)
[  138.425898][    C1]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[  138.425903][    C1]  ife_encode_meta_u16 (net/sched/act_ife.c:57)
[  138.425910][    C1]  ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114)
[  138.425916][    C1]  ? __asan_memcpy (mm/kasan/shadow.c:105 (discriminator 3))
[  138.425921][    C1]  ? __pfx_ife_encode_meta_u16 (net/sched/act_ife.c:45)
[  138.425927][    C1]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[  138.425931][    C1]  tcf_ife_act (net/sched/act_ife.c:847 net/sched/act_ife.c:879)

To solve this issue, fix the replace behavior by adding the metalist to
the ife rcu data structure.

Comment 1 Alexander B 2026-03-25 11:48:15 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026032542-CVE-2026-23378-f329@gregkh/T