In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_flower: validate mask pointer after nla_next()
fl_set_enc_opt() iterates the key's nested tunnel-option attributes
with nla_for_each_attr() while advancing a single mask pointer via
nla_next() at the bottom of each loop, so the mask cursor is driven
by the number of key attributes rather than by the mask's own
attributes. The nla_ok() added by commit c96adff956191 ("cls_flower:
call nla_ok() before nla_next()") only validates the mask pointer
that was just consumed; the pointer produced by nla_next() is used by
the next iteration (fl_set_geneve_opt() and siblings) without any
validation.
The mask's nested attributes are validated with NL_VALIDATE_LIBERAL,
which merely warns on trailing bytes that do not form a complete
attribute. A mask carrying one valid attribute plus 1-3 residue
bytes (or a non-aligned attribute length making msk_depth negative)
therefore reaches the next iteration with msk_depth != 0, so neither
the !msk_depth check in fl_set_enc_opt() nor the !depth check in the
per-type helpers fires. nla_type() then reads past the mask payload
and nla_parse_nested_deprecated() iterates with an nla_len taken
from those bytes, reading well beyond the mask attribute (KASAN:
slab-out-of-bounds read in __nla_validate_parse from fl_change()).
Validate the advanced mask pointer as well: when the mask is not
legitimately exhausted (msk_depth != 0) and the new pointer fails
nla_ok(), reject the filter with -EINVAL. An exactly exhausted mask
still skips the check, preserving exact-match behaviour for the
remaining key attributes.
net/sched: cls_flower: validate mask pointer after nla_next()
fl_set_enc_opt() iterates the key's nested tunnel-option attributes
with nla_for_each_attr() while advancing a single mask pointer via
nla_next() at the bottom of each loop, so the mask cursor is driven
by the number of key attributes rather than by the mask's own
attributes. The nla_ok() added by commit c96adff956191 ("cls_flower:
call nla_ok() before nla_next()") only validates the mask pointer
that was just consumed; the pointer produced by nla_next() is used by
the next iteration (fl_set_geneve_opt() and siblings) without any
validation.
The mask's nested attributes are validated with NL_VALIDATE_LIBERAL,
which merely warns on trailing bytes that do not form a complete
attribute. A mask carrying one valid attribute plus 1-3 residue
bytes (or a non-aligned attribute length making msk_depth negative)
therefore reaches the next iteration with msk_depth != 0, so neither
the !msk_depth check in fl_set_enc_opt() nor the !depth check in the
per-type helpers fires. nla_type() then reads past the mask payload
and nla_parse_nested_deprecated() iterates with an nla_len taken
from those bytes, reading well beyond the mask attribute (KASAN:
slab-out-of-bounds read in __nla_validate_parse from fl_change()).
Validate the advanced mask pointer as well: when the mask is not
legitimately exhausted (msk_depth != 0) and the new pointer fails
nla_ok(), reject the filter with -EINVAL. An exactly exhausted mask
still skips the check, preserving exact-match behaviour for the
remaining key attributes.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
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| Vendors | Products |
|---|---|
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Linux
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 28 Oct 2026 13:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 CWE-788 |
Wed, 28 Oct 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux linux
|
|
| Vendors & Products |
Linux linux
|
Wed, 28 Oct 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_flower: validate mask pointer after nla_next() fl_set_enc_opt() iterates the key's nested tunnel-option attributes with nla_for_each_attr() while advancing a single mask pointer via nla_next() at the bottom of each loop, so the mask cursor is driven by the number of key attributes rather than by the mask's own attributes. The nla_ok() added by commit c96adff956191 ("cls_flower: call nla_ok() before nla_next()") only validates the mask pointer that was just consumed; the pointer produced by nla_next() is used by the next iteration (fl_set_geneve_opt() and siblings) without any validation. The mask's nested attributes are validated with NL_VALIDATE_LIBERAL, which merely warns on trailing bytes that do not form a complete attribute. A mask carrying one valid attribute plus 1-3 residue bytes (or a non-aligned attribute length making msk_depth negative) therefore reaches the next iteration with msk_depth != 0, so neither the !msk_depth check in fl_set_enc_opt() nor the !depth check in the per-type helpers fires. nla_type() then reads past the mask payload and nla_parse_nested_deprecated() iterates with an nla_len taken from those bytes, reading well beyond the mask attribute (KASAN: slab-out-of-bounds read in __nla_validate_parse from fl_change()). Validate the advanced mask pointer as well: when the mask is not legitimately exhausted (msk_depth != 0) and the new pointer fails nla_ok(), reject the filter with -EINVAL. An exactly exhausted mask still skips the check, preserving exact-match behaviour for the remaining key attributes. | |
| Title | net/sched: cls_flower: validate mask pointer after nla_next() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-28T10:34:29.881Z
Reserved: 2026-09-25T10:25:14.392Z
Link: CVE-2026-99112
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-28T11:17:30.640
Modified: 2026-10-28T11:17:30.640
Link: CVE-2026-99112
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-10-28T12:45:16Z