Vulnerability Details CVE-2026-31641
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix RxGK token loading to check bounds
rxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length
from the XDR token as u32 values and passes each through round_up(x, 4)
before using the rounded value for validation and allocation. When the raw
length is >= 0xfffffffd, round_up() wraps to 0, so the bounds check and
kzalloc both use 0 while the subsequent memcpy still copies the original
~4 GiB value, producing a heap buffer overflow reachable from an
unprivileged add_key() call.
Fix this by:
(1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket
lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with
the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX.
(2) Sizing the flexible-array allocation from the validated raw key
length via struct_size_t() instead of the rounded value.
(3) Caching the raw lengths so that the later field assignments and
memcpy calls do not re-read from the token, eliminating a class of
TOCTOU re-parse.
The control path (valid token with lengths within bounds) is unaffected.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 4.1%
CVSS Severity
CVSS v3 Score 7.8
Products affected by CVE-2026-31641
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cpe:2.3:o:linux:linux_kernel:6.16
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cpe:2.3:o:linux:linux_kernel:6.16.1
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cpe:2.3:o:linux:linux_kernel:6.16.10
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cpe:2.3:o:linux:linux_kernel:6.16.11
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cpe:2.3:o:linux:linux_kernel:6.16.12
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cpe:2.3:o:linux:linux_kernel:6.16.2
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cpe:2.3:o:linux:linux_kernel:6.16.3
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cpe:2.3:o:linux:linux_kernel:6.16.4
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cpe:2.3:o:linux:linux_kernel:6.16.5
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cpe:2.3:o:linux:linux_kernel:6.16.6
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cpe:2.3:o:linux:linux_kernel:6.16.7
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cpe:2.3:o:linux:linux_kernel:6.16.8
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cpe:2.3:o:linux:linux_kernel:6.16.9
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cpe:2.3:o:linux:linux_kernel:6.17
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cpe:2.3:o:linux:linux_kernel:6.17.1
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cpe:2.3:o:linux:linux_kernel:6.17.10
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cpe:2.3:o:linux:linux_kernel:6.17.11
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cpe:2.3:o:linux:linux_kernel:6.17.12
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cpe:2.3:o:linux:linux_kernel:6.17.13
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cpe:2.3:o:linux:linux_kernel:6.17.2
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cpe:2.3:o:linux:linux_kernel:6.17.3
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cpe:2.3:o:linux:linux_kernel:6.17.4
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cpe:2.3:o:linux:linux_kernel:6.17.5
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cpe:2.3:o:linux:linux_kernel:6.17.6
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cpe:2.3:o:linux:linux_kernel:6.17.7
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cpe:2.3:o:linux:linux_kernel:6.17.8
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cpe:2.3:o:linux:linux_kernel:6.17.9
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cpe:2.3:o:linux:linux_kernel:6.18
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cpe:2.3:o:linux:linux_kernel:6.18.1
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cpe:2.3:o:linux:linux_kernel:6.18.10
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cpe:2.3:o:linux:linux_kernel:6.18.11
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cpe:2.3:o:linux:linux_kernel:6.18.13
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cpe:2.3:o:linux:linux_kernel:6.18.14
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cpe:2.3:o:linux:linux_kernel:6.18.2
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cpe:2.3:o:linux:linux_kernel:6.18.3
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cpe:2.3:o:linux:linux_kernel:6.18.4
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cpe:2.3:o:linux:linux_kernel:6.18.5
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cpe:2.3:o:linux:linux_kernel:6.18.6
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cpe:2.3:o:linux:linux_kernel:6.18.7
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cpe:2.3:o:linux:linux_kernel:6.18.8
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cpe:2.3:o:linux:linux_kernel:6.18.9
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cpe:2.3:o:linux:linux_kernel:6.19
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cpe:2.3:o:linux:linux_kernel:6.19.1
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cpe:2.3:o:linux:linux_kernel:6.19.3
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cpe:2.3:o:linux:linux_kernel:6.19.4
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cpe:2.3:o:linux:linux_kernel:7.0