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TI-2025-15604 Aliases CVE-2025-21647GHSA-j2g7-wj3p-j9c9

sched: sch_cake: add bounds checks to host bulk flow fairness counts

Priority LOW 32CWE-125Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · Low · High
Fix status
Partial Red Hat: 15 fixed, 1 without a fix

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

Summary

In the Linux kernel, the following vulnerability has been resolved: sched: sch_cake: add bounds checks to host bulk flow fairness counts Even though we fixed a logic error in the commit cited below, syzbot still managed to trigger an underflow of the per-host bulk flow counters, leading to an out of bounds memory access. To avoid any such logic errors causing out of bounds memory accesses, this commit factors out all accesses to the per-host bulk flow counters to a series of helpers that perform bounds-checking before any increments and decrements. This also has the benefit of improving readability by moving the conditional checks for the flow mode into these helpers, instead of having them spread out throughout the code (which was the cause of the original logic error). As part of this change, the flow quantum calculation is consolidated into a helper function, which means that the dithering applied to the ost load scaling is now applied both in the DRR rotation and when a sparse flow's quantum is first initiated. The only user-visible effect of this is that the maximum packet size that can be sent while a flow stays sparse will now vary with +/- one byte in some cases. This should not make a noticeable difference in practice, and thus it's not worth complicating the code to preserve the old behaviour.

Why it matters now

EPSS 0.00284 21st percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.4.291, 5.10.235, 5.15.179 +5Red Hat: 3 advisoriesRed Hat: 15 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.4.284 to before 5.4.291; 5.10.226 to before 5.10.235; 5.15.167 to before 5.15.179; 6.1.110 to before 6.1.125; 6.6.51 to before 6.6.72; 6.10.10 to before 6.115.4.291, 5.10.235, 5.15.179, 6.1.125, 6.6.72, 6.11Patch availableCNA
LinuxLinux6.11 and later5.4.291, 5.10.235, 5.15.179, 6.1.125, 6.6.72, 6.12.10, 6.13Patch availableCNA
  • Linux VendorLinux Affected 5.4.284 to before 5.4.291; 5.10.226 to before 5.10.235; 5.15.167 to before 5.15.179; 6.1.110 to before 6.1.125; 6.6.51 to before 6.6.72; 6.10.10 to before 6.11 Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.125, 6.6.72, 6.11 Patch available CNA
  • Linux VendorLinux Affected 6.11 and later Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.125, 6.6.72, 6.12.10, 6.13 Patch available CNA

CPE configurations NVD · 9

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.4.284 to before 5.4.291; 5.10.226 to before 5.10.235; 5.15.167 to before 5.15.179; 6.1.110 to before 6.1.125; 6.6.51 to before 6.6.72; 6.10.10 to before 6.11; 6.11.1 to before 6.12.10VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:-:*:*:*:*:*:*6.11VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:*6.11 rc7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:*6.13 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:*6.13 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:*6.13 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:*6.13 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:*6.13 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:*6.13 rc6VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.4.284 to before 5.4.291; 5.10.226 to before 5.10.235; 5.15.167 to before 5.15.179; 6.1.110 to before 6.1.125; 6.6.51 to before 6.6.72; 6.10.10 to before 6.11; 6.11.1 to before 6.12.10 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:-:*:*:*:*:*:* Versions 6.11 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:* Versions 6.11 rc7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* Versions 6.13 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* Versions 6.13 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* Versions 6.13 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:* Versions 6.13 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:* Versions 6.13 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:* Versions 6.13 rc6 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.125, 6.6.72, 6.11
  • Fix · CNA Linux (Linux) Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.125, 6.6.72, 6.12.10, 6.13

Red Hat 3 advisories

  • RHSA-2026:2352 Released 2026-02-09 · Red Hat rating Moderate
    kernel security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.86.1.el9_6, libperf-5.14.0-570.86.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.86.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.86.1.el9_6, kernel-64k-devel-5.14.0-570.86.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.86.1.el9_6, kernel-64k-5.14.0-570.86.1.el9_6, kernel-64k-core-5.14.0-570.86.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.86.1.el9_6, kernel-rt-64k-5.14.0-570.86.1.el9_6, kernel-rt-64k-core-5.14.0-570.86.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.86.1.el9_6, kernel-rt-core-5.14.0-570.86.1.el9_6, kernel-rt-debug-5.14.0-570.86.1.el9_6 +11
  • RHSA-2025:20518 Released 2025-11-11 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-611.5.1.el9_7, kernel-64k-debug-devel-matched-5.14.0-611.5.1.el9_7, kernel-64k-devel-5.14.0-611.5.1.el9_7 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-611.5.1.el9_7, kernel-64k-5.14.0-611.5.1.el9_7, kernel-64k-core-5.14.0-611.5.1.el9_7 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-611.5.1.el9_7, libperf-5.14.0-611.5.1.el9_7
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-611.5.1.el9_7, kernel-rt-64k-5.14.0-611.5.1.el9_7, kernel-rt-64k-core-5.14.0-611.5.1.el9_7 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-611.5.1.el9_7, kernel-rt-core-5.14.0-611.5.1.el9_7, kernel-rt-debug-5.14.0-611.5.1.el9_7 +9
  • RHSA-2025:20095 Released 2025-11-11 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-124.8.1.el10_1, kernel-64k-debug-devel-matched-6.12.0-124.8.1.el10_1, kernel-64k-devel-6.12.0-124.8.1.el10_1 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-124.8.1.el10_1, kernel-64k-6.12.0-124.8.1.el10_1, kernel-64k-core-6.12.0-124.8.1.el10_1 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-124.8.1.el10_1, libperf-6.12.0-124.8.1.el10_1
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-124.8.1.el10_1, kernel-rt-64k-6.12.0-124.8.1.el10_1, kernel-rt-64k-core-6.12.0-124.8.1.el10_1 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-124.8.1.el10_1, kernel-rt-core-6.12.0-124.8.1.el10_1, kernel-rt-debug-6.12.0-124.8.1.el10_1 +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.9.6)Fixed RHSA-2026:2352
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2025:20095
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2025:20518
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:2352
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2025:20095
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2025:20518
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:2352
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2025:20095
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2025:20518
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2025:20095
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2025:20518
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:2352
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2025:20095
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2025:20518
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:2352
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-2025-21647
  2. 2026-10-03 Alias added: GHSA-j2g7-wj3p-j9c9

References

Patch 7

  • 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