Linux Kernel Stack OOB Read in netfilter nft_set_pipapo
CVE-2026-43453 Published on May 8, 2026
netfilter: nft_set_pipapo: fix stack out-of-bounds read in pipapo_drop()
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_set_pipapo: fix stack out-of-bounds read in pipapo_drop()
pipapo_drop() passes rulemap[i + 1].n to pipapo_unmap() as the
to_offset argument on every iteration, including the last one where
i == m->field_count - 1. This reads one element past the end of the
stack-allocated rulemap array (declared as rulemap[NFT_PIPAPO_MAX_FIELDS]
with NFT_PIPAPO_MAX_FIELDS == 16).
Although pipapo_unmap() returns early when is_last is true without
using the to_offset value, the argument is evaluated at the call site
before the function body executes, making this a genuine out-of-bounds
stack read confirmed by KASAN:
BUG: KASAN: stack-out-of-bounds in pipapo_drop+0x50c/0x57c [nf_tables]
Read of size 4 at addr ffff8000810e71a4
This frame has 1 object:
[32, 160) 'rulemap'
The buggy address is at offset 164 -- exactly 4 bytes past the end
of the rulemap array.
Pass 0 instead of rulemap[i + 1].n on the last iteration to avoid
the out-of-bounds read.
Products Associated with CVE-2026-43453
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Affected Versions
Linux:- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below 1957e793196e7f8557374fd4eda53abcbb42e1c0 is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below 57fb87ca095d5127cd7a27583b8ec43dcf7c9e9e is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below 60c1d18781e37bfb96290b86510eb01c5fa24d75 is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below 0a55d62cdb628923d8a21724374a70c76ac7d19d is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below dfbdac719198778b581bc0dd055df2542edb8c62 is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below e047f6fbb975f685d6c9fcef95b3b7787a79b46d is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below 324b749aa5b2d516ccfab933df9d3f56e7807f5f is affected.
- Version 3c4287f62044a90e73a561aa05fc46e62da173da and below d6d8cd2db236a9dd13dbc2d05843b3445cc964b5 is affected.
- Version 5.6 is affected.
- Before 5.6 is unaffected.
- Version 5.10.253, <= 5.10.* is unaffected.
- Version 5.15.203, <= 5.15.* is unaffected.
- Version 6.1.167, <= 6.1.* is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.19, <= 6.18.* is unaffected.
- Version 6.19.9, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.