cbcvebase.
CVE-2025-21647
published 2025-01-19

CVE-2025-21647: 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…

PriorityP432high7.1CVSS 3.1
AVLACLPRLUINSUCHINAH
EPSS
0.28%
20.1th percentile
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.

Affected

39 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.128-1 (bookworm)linux 6.1.128-1 (bookworm)
debianlinux-6.1< linux 6.1.128-1 (bookworm)linux 6.1.128-1 (bookworm)
linuxlinux
linuxlinux
linuxlinux>= 4a4eeefa514db570be025ab46d779af180e2c9bb < 44fe1efb4961c1a5ccab16bb579dfc6b308ad58b44fe1efb4961c1a5ccab16bb579dfc6b308ad58b
linuxlinux>= 5.10.226 < 5.10.2355.10.235
linuxlinux>= 5.15.167 < 5.15.1795.15.179
linuxlinux>= 5.4.284 < 5.4.2915.4.291
linuxlinux>= 546ea84d07e3e324644025e2aae2d12ea4c5896e < 91bb18950b88f955838ec0c1d97f74d135756dc791bb18950b88f955838ec0c1d97f74d135756dc7
linuxlinux>= 546ea84d07e3e324644025e2aae2d12ea4c5896e < 737d4d91d35b5f7fa5bb442651472277318b0bfd737d4d91d35b5f7fa5bb442651472277318b0bfd
linuxlinux>= 549e407569e08459d16122341d332cb508024094 < a777e06dfc72bed73c05dcb437d7c27ad5f90f3fa777e06dfc72bed73c05dcb437d7c27ad5f90f3f
linuxlinux>= 6.1.110 < 6.1.1256.1.125
linuxlinux>= 6.10.10 < 6.116.11
linuxlinux>= 6.6.51 < 6.6.726.6.72
linuxlinux>= 7725152b54d295b7da5e34c2f419539b30d017bd < b1a1743aaa4906c41c426eda97e2e2586f79246db1a1743aaa4906c41c426eda97e2e2586f79246d
linuxlinux>= cde71a5677971f4f1b69b25e854891dbe78066a4 < bb0245fa72b783cb23a9949c5048781341e91423bb0245fa72b783cb23a9949c5048781341e91423
linuxlinux>= d4a9039a7b3d8005b90c7b1a55a306444f0e5447 < 27202e2e8721c3b23831563c36ed5ac7818641ba27202e2e8721c3b23831563c36ed5ac7818641ba
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel

CVSS provenance

nvdv3.17.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.1HIGH
vendor_redhat7.1HIGH
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