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TI-2025-26441 Aliases CVE-2025-39766GHSA-p46x-ph7h-c256

net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit

Priority LOW 35Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 29 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit The following setup can trigger a WARNING in htb_activate due to the condition: !cl->leaf.q->q.qlen tc qdisc del dev lo root tc qdisc add dev lo root handle 1: htb default 1 tc class add dev lo parent 1: classid 1:1 \ htb rate 64bit tc qdisc add dev lo parent 1:1 handle f: \ cake memlimit 1b ping -I lo -f -c1 -s64 -W0.001 127.0.0.1 This is because the low memlimit leads to a low buffer_limit, which causes packet dropping. However, cake_enqueue still returns NET_XMIT_SUCCESS, causing htb_enqueue to call htb_activate with an empty child qdisc. We should return NET_XMIT_CN when packets are dropped from the same tin and flow. I do not believe return value of NET_XMIT_CN is necessary for packet drops in the case of ack filtering, as that is meant to optimize performance, not to signal congestion.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00184 8th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.4.297, 5.10.241, 5.15.190 +5Red Hat: 9 advisoriesRed Hat: 29 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux4.19 and later5.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.44, 6.16.4, 6.17Patch availableCNA
  • Linux VendorLinux Affected 4.19 and later Fixed in 5.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.44, 6.16.4, 6.17 Patch available CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.19 to before 5.4.297; 5.5 to before 5.10.241; 5.11 to before 5.15.190; 5.16 to before 6.1.149; 6.2 to before 6.6.103; 6.7 to before 6.12.44; 6.13 to before 6.16.4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*6.17 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*6.17 rc2VulnerableLinux
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*11.0VulnerableDebian
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.19 to before 5.4.297; 5.5 to before 5.10.241; 5.11 to before 5.15.190; 5.16 to before 6.1.149; 6.2 to before 6.6.103; 6.7 to before 6.12.44; 6.13 to before 6.16.4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* Versions 6.17 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* Versions 6.17 rc2 Vulnerable ·Linux
  • cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.44, 6.16.4, 6.17

Red Hat 9 advisories

  • RHSA-2026:23224 Released 2026-06-04 · Red Hat rating Important
    kernel security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.119.1.el9_6, libperf-5.14.0-570.119.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.119.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.119.1.el9_6, kernel-64k-devel-5.14.0-570.119.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.119.1.el9_6, kernel-64k-5.14.0-570.119.1.el9_6, kernel-64k-core-5.14.0-570.119.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.119.1.el9_6, kernel-rt-64k-5.14.0-570.119.1.el9_6, kernel-rt-64k-core-5.14.0-570.119.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.119.1.el9_6, kernel-rt-core-5.14.0-570.119.1.el9_6, kernel-rt-debug-5.14.0-570.119.1.el9_6 +11
  • RHSA-2026:22940 Released 2026-06-03 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.174.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.174.1.el9_2, kernel-64k-devel-5.14.0-284.174.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.174.1.el9_2, kernel-5.14.0-284.174.1.el9_2, kernel-64k-5.14.0-284.174.1.el9_2 +29
  • RHSA-2026:22900 Released 2026-06-03 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-core-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-debug-5.14.0-284.174.1.rt14.459.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-core-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-debug-5.14.0-284.174.1.rt14.459.el9_2 +11
Show 6 more Red Hat advisories
  • RHSA-2026:22334 Released 2026-06-01 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.76.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.76.1.el10_0, kernel-64k-devel-6.12.0-55.76.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.76.1.el10_0, kernel-64k-6.12.0-55.76.1.el10_0, kernel-64k-core-6.12.0-55.76.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.76.1.el10_0, libperf-6.12.0-55.76.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.76.1.el10_0, kernel-rt-64k-6.12.0-55.76.1.el10_0, kernel-rt-64k-core-6.12.0-55.76.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.76.1.el10_0, kernel-rt-core-6.12.0-55.76.1.el10_0, kernel-rt-debug-6.12.0-55.76.1.el10_0 +11
  • RHSA-2026:21209 Released 2026-05-27 · Red Hat rating Important
    kernel security update
    • Red Hat CodeReady Linux Builder EUS (v.9.4) kernel-tools-libs-devel-5.14.0-427.127.1.el9_4, libperf-5.14.0-427.127.1.el9_4
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) kernel-64k-debug-devel-5.14.0-427.127.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.127.1.el9_4, kernel-64k-devel-5.14.0-427.127.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool-7.3.0-427.127.1.el9_4, kernel-5.14.0-427.127.1.el9_4, kernel-64k-5.14.0-427.127.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt-5.14.0-427.127.1.el9_4, kernel-rt-core-5.14.0-427.127.1.el9_4, kernel-rt-debug-5.14.0-427.127.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt-5.14.0-427.127.1.el9_4, kernel-rt-core-5.14.0-427.127.1.el9_4, kernel-rt-debug-5.14.0-427.127.1.el9_4 +11
  • RHSA-2026:19568 Released 2026-05-20 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.10.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.10.1.el9_8, kernel-64k-devel-5.14.0-687.10.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.10.1.el9_8, kernel-64k-5.14.0-687.10.1.el9_8, kernel-64k-core-5.14.0-687.10.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.10.1.el9_8, libperf-5.14.0-687.10.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.10.1.el9_8, kernel-rt-64k-5.14.0-687.10.1.el9_8, kernel-rt-64k-core-5.14.0-687.10.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.10.1.el9_8, kernel-rt-core-5.14.0-687.10.1.el9_8, kernel-rt-debug-5.14.0-687.10.1.el9_8 +9
  • RHSA-2026:19569 Released 2026-05-20 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.16.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.16.1.el10_2, kernel-64k-devel-6.12.0-211.16.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.16.1.el10_2, kernel-64k-6.12.0-211.16.1.el10_2, kernel-64k-core-6.12.0-211.16.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.16.1.el10_2, libperf-6.12.0-211.16.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.16.1.el10_2, kernel-rt-64k-6.12.0-211.16.1.el10_2, kernel-rt-64k-core-6.12.0-211.16.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.16.1.el10_2, kernel-rt-core-6.12.0-211.16.1.el10_2, kernel-rt-debug-6.12.0-211.16.1.el10_2 +9
  • RHSA-2026:9264 Released 2026-04-21 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-124.52.1.el10_1, kernel-64k-debug-devel-matched-6.12.0-124.52.1.el10_1, kernel-64k-devel-6.12.0-124.52.1.el10_1 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-124.52.1.el10_1, kernel-64k-6.12.0-124.52.1.el10_1, kernel-64k-core-6.12.0-124.52.1.el10_1 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-124.52.1.el10_1, libperf-6.12.0-124.52.1.el10_1
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-124.52.1.el10_1, kernel-rt-64k-6.12.0-124.52.1.el10_1, kernel-rt-64k-core-6.12.0-124.52.1.el10_1 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-124.52.1.el10_1, kernel-rt-core-6.12.0-124.52.1.el10_1, kernel-rt-debug-6.12.0-124.52.1.el10_1 +9
  • RHSA-2026:8921 Released 2026-04-20 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-611.49.1.el9_7, kernel-64k-debug-devel-matched-5.14.0-611.49.1.el9_7, kernel-64k-devel-5.14.0-611.49.1.el9_7 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-611.49.1.el9_7, kernel-64k-5.14.0-611.49.1.el9_7, kernel-64k-core-5.14.0-611.49.1.el9_7 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-611.49.1.el9_7, libperf-5.14.0-611.49.1.el9_7
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-611.49.1.el9_7, kernel-rt-64k-5.14.0-611.49.1.el9_7, kernel-rt-64k-core-5.14.0-611.49.1.el9_7 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-611.49.1.el9_7, kernel-rt-core-5.14.0-611.49.1.el9_7, kernel-rt-debug-5.14.0-611.49.1.el9_7 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat CodeReady Linux Builder EUS (v.9.4)Fixed RHSA-2026:21209
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:19569, RHSA-2026:9264
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:19568, RHSA-2026:8921
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:22940
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:22334
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2026:21209
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:19569, RHSA-2026:9264
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:19568, RHSA-2026:8921
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:22940
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:22334
Red Hat Enterprise Linux BaseOS EUS (v.9.4)Fixed RHSA-2026:21209
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:19569, RHSA-2026:9264
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:19568, RHSA-2026:8921
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:22334
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:19569, RHSA-2026:9264
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:19568, RHSA-2026:8921
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:22900
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:22334
Red Hat Enterprise Linux Real Time EUS (v.9.4)Fixed RHSA-2026:21209
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:19569, RHSA-2026:9264
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:19568, RHSA-2026:8921
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2026:22900
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:22334
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4)Fixed RHSA-2026:21209
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:23224
Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-39766
  2. 2026-10-03 Alias added: GHSA-p46x-ph7h-c256

References

Patch 8

Advisory 2

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences