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Fencer Vulns
high 7.1

CVE-2024-26669 json

net/sched: flower: Fix chain template offload

published 2024-04-02 2 y ago modified 2026-10-30 10 d ago also EUVD-2024-23931

cvss
7.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

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

net/sched: flower: Fix chain template offload

When a qdisc is deleted from a net device the stack instructs the underlying driver to remove its flow offload callback from the associated filter block using the 'FLOW_BLOCK_UNBIND' command. The stack then continues to replay the removal of the filters in the block for this driver by iterating over the chains in the block and invoking the 'reoffload' operation of the classifier being used. In turn, the classifier in its 'reoffload' operation prepares and emits a 'FLOW_CLS_DESTROY' command for each filter.

However, the stack does not do the same for chain templates and the underlying driver never receives a 'FLOW_CLS_TMPLT_DESTROY' command when a qdisc is deleted. This results in a memory leak [1] which can be reproduced using [2].

Fix by introducing a 'tmplt_reoffload' operation and have the stack invoke it with the appropriate arguments as part of the replay. Implement the operation in the sole classifier that supports chain templates (flower) by emitting the 'FLOW_CLS_TMPLT_{CREATE,DESTROY}' command based on whether a flow offload callback is being bound to a filter block or being unbound from one.

As far as I can tell, the issue happens since cited commit which reordered tcf_block_offload_unbind() before tcf_block_flush_all_chains() in __tcf_block_put(). The order cannot be reversed as the filter block is expected to be freed after flushing all the chains.

[1] unreferenced object 0xffff888107e28800 (size 2048): comm "tc", pid 1079, jiffies 4294958525 (age 3074.287s) hex dump (first 32 bytes): b1 a6 7c 11 81 88 ff ff e0 5b b3 10 81 88 ff ff ..|......[...... 01 00 00 00 00 00 00 00 e0 aa b0 84 ff ff ff ff ................ backtrace: [<ffffffff81c06a68>] __kmem_cache_alloc_node+0x1e8/0x320 [<ffffffff81ab374e>] __kmalloc+0x4e/0x90 [<ffffffff832aec6d>] mlxsw_sp_acl_ruleset_get+0x34d/0x7a0 [<ffffffff832bc195>] mlxsw_sp_flower_tmplt_create+0x145/0x180 [<ffffffff832b2e1a>] mlxsw_sp_flow_block_cb+0x1ea/0x280 [<ffffffff83a10613>] tc_setup_cb_call+0x183/0x340 [<ffffffff83a9f85a>] fl_tmplt_create+0x3da/0x4c0 [<ffffffff83a22435>] tc_ctl_chain+0xa15/0x1170 [<ffffffff838a863c>] rtnetlink_rcv_msg+0x3cc/0xed0 [<ffffffff83ac87f0>] netlink_rcv_skb+0x170/0x440 [<ffffffff83ac6270>] netlink_unicast+0x540/0x820 [<ffffffff83ac6e28>] netlink_sendmsg+0x8d8/0xda0 [<ffffffff83793def>] ____sys_sendmsg+0x30f/0xa80 [<ffffffff8379d29a>] ___sys_sendmsg+0x13a/0x1e0 [<ffffffff8379d50c>] __sys_sendmsg+0x11c/0x1f0 [<ffffffff843b9ce0>] do_syscall_64+0x40/0xe0 unreferenced object 0xffff88816d2c0400 (size 1024): comm "tc", pid 1079, jiffies 4294958525 (age 3074.287s) hex dump (first 32 bytes): 40 00 00 00 00 00 00 00 57 f6 38 be 00 00 00 00 @.......W.8..... 10 04 2c 6d 81 88 ff ff 10 04 2c 6d 81 88 ff ff ..,m......,m.... backtrace: [<ffffffff81c06a68>] __kmem_cache_alloc_node+0x1e8/0x320 [<ffffffff81ab36c1>] __kmalloc_node+0x51/0x90 [<ffffffff81a8ed96>] kvmalloc_node+0xa6/0x1f0 [<ffffffff82827d03>] bucket_table_alloc.isra.0+0x83/0x460 [<ffffffff82828d2b>] rhashtable_init+0x43b/0x7c0 [<ffffffff832aed48>] mlxsw_sp_acl_ruleset_get+0x428/0x7a0 [<ffffffff832bc195>] mlxsw_sp_flower_tmplt_create+0x145/0x180 [<ffffffff832b2e1a>] mlxsw_sp_flow_block_cb+0x1ea/0x280 [<ffffffff83a10613>] tc_setup_cb_call+0x183/0x340 [<ffffffff83a9f85a>] fl_tmplt_create+0x3da/0x4c0 [<ffffffff83a22435>] tc_ctl_chain+0xa15/0x1170 [<ffffffff838a863c>] rtnetlink_rcv_msg+0x3cc/0xed0 [<ffffffff83ac87f0>] netlink_rcv_skb+0x170/0x440 [<ffffffff83ac6270>] netlink_unicast+0x540/0x820 [<ffffffff83ac6e28>] netlink_sendmsg+0x8d8/0xda0 [<ffffffff83793def>] ____sys_sendmsg+0x30f/0xa80

[2] # tc qdisc add dev swp1 clsact # tc chain add dev swp1 ingress proto ip chain 1 flower dst_ip 0.0.0.0/32 # tc qdisc del dev ---truncated---

Patch / fix

  • Linux Linux 6.1.191, 6.6.15, 6.7.3, 6.8
  • linux Debian 14, Debian 13 6.6.15-1

debian advisories DEBIAN-CVE-2024-26669

  • linux Ubuntu 20.04 LTS 5.4.0-200.220
  • linux Ubuntu 22.04 LTS 5.15.0-125.135
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1135.145
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1072.78
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1139.148
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1071.79
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1069.75
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1082.87

ubuntu advisories UBUNTU-CVE-2024-26669

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-503.11.1.el9_5
  • rv RHEL 9 5.14.0-503.11.1.el9_5
  • perf RHEL 9 5.14.0-503.11.1.el9_5
  • rtla RHEL 9 5.14.0-503.11.1.el9_5
  • bpftool RHEL 9 7.4.0-503.11.1.el9_5
  • libperf RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-rt RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-64k RHEL 9 5.14.0-503.11.1.el9_5

red hat advisories RHSA-2025:9584RHSA-2024:9315RHSA-2024:5102RHSA-2024:5101

  • kernel-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-livepatch-MICRO-6-0-RT_Update_2 Linux Micro 6.0 1-1.1
  • kernel-source Linux Micro 6.0 6.4.0-19.1
  • kernel-default Linux Micro 6.0 6.4.0-19.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-19.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-livepatch-MICRO-6-0_Update_2 Linux Micro 6.0 1-1.1

suse advisories SUSE-SU-2025:20047-1SUSE-SU-2025:20044-1SUSE-SU-2024:3483-1SUSE-SU-2024:3383-1SUSE-SU-2024:3209-1SUSE-SU-2024:3195-1

  • kernel AlmaLinux 8 4.18.0-553.16.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.16.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.16.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.16.1.el8_10

almalinux advisories ALSA-2024:5101ALSA-2024:5102

  • kernel Rocky Linux 8 4.18.0-553.16.1.el8_10.cloud.0.1
  • kernel-rt Rocky Linux 8 4.18.0-553.16.1.rt7.357.el8_10
  • kernel Rocky Linux 8 4.18.0-553.16.1.el8_10

rocky linux advisories RXSA-2024:5101RLSA-2024:5102RLSA-2024:5101

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-26669 updated cvss 7.1

kernel: net/sched: flower: Fix chain template offload

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 9) libperf 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-s390x 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-x86_64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-aarch64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-ppc64le 5.14.0-503.11.1.el9_5
    fixed: vendor fix RHSA-2024:9315
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.74.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.74.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.74.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.74.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.74.1.el9_4
    fixed: vendor fix RHSA-2025:9584
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-503.11.1.el9_5, perf 5.14.0-503.11.1.el9_5, rtla 5.14.0-503.11.1.el9_5, kernel-devel-matched 5.14.0-503.11.1.el9_5, kernel-64k-devel-matched 5.14.0-503.11.1.el9_5, kernel-debug-devel-matched 5.14.0-503.11.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.74.1.el9_4, perf 5.14.0-427.74.1.el9_4, rtla 5.14.0-427.74.1.el9_4, kernel-devel-matched 5.14.0-427.74.1.el9_4, kernel-64k-devel-matched 5.14.0-427.74.1.el9_4, kernel-debug-devel-matched 5.14.0-427.74.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:9584
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.16.1.el8_10, kernel 4.18.0-553.16.1.el8_10, bpftool 4.18.0-553.16.1.el8_10, kernel-core 4.18.0-553.16.1.el8_10, kernel-tools 4.18.0-553.16.1.el8_10, python3-perf 4.18.0-553.16.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:5101
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.4.0-503.11.1.el9_5, kernel 5.14.0-503.11.1.el9_5, kernel-64k 5.14.0-503.11.1.el9_5, kernel-core 5.14.0-503.11.1.el9_5, kernel-tools 5.14.0-503.11.1.el9_5, python3-perf 5.14.0-503.11.1.el9_5, +29 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.74.1.el9_4, kernel 5.14.0-427.74.1.el9_4, kernel-64k 5.14.0-427.74.1.el9_4, kernel-core 5.14.0-427.74.1.el9_4, kernel-tools 5.14.0-427.74.1.el9_4, python3-perf 5.14.0-427.74.1.el9_4, +28 more
    fixed: vendor fix RHSA-2025:9584
show 8 more
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.16.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.16.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.16.1.el8_10
    fixed: vendor fix RHSA-2024:5101
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-kvm 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-core 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-modules 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-kvm 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-core 4.18.0-553.16.1.rt7.357.el8_10, +4 more
    fixed: vendor fix RHSA-2024:5102
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, kernel-rt-modules-core 5.14.0-503.11.1.el9_5, kernel-rt-debug-modules 5.14.0-503.11.1.el9_5, +4 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.74.1.el9_4, kernel-rt-core 5.14.0-427.74.1.el9_4, kernel-rt-modules 5.14.0-427.74.1.el9_4, kernel-rt-debug-core 5.14.0-427.74.1.el9_4, kernel-rt-modules-core 5.14.0-427.74.1.el9_4, kernel-rt-debug-modules 5.14.0-427.74.1.el9_4, +4 more
    fixed: vendor fix RHSA-2025:9584
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-kvm 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-kvm 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.74.1.el9_4, kernel-rt-kvm 5.14.0-427.74.1.el9_4, kernel-rt-core 5.14.0-427.74.1.el9_4, kernel-rt-modules 5.14.0-427.74.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.74.1.el9_4, kernel-rt-debug-core 5.14.0-427.74.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:9584
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-core 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-modules 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-core 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-modules 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-modules-extra 4.18.0-553.16.1.rt7.357.el8_10, +2 more
    fixed: vendor fix RHSA-2024:5102
  • Red Hat CodeReady Linux Builder (v. 9) kernel-cross-headers 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux AppStream (v. 9) kernel-headers 5.14.0-503.11.1.el9_5
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.