# CVE-2026-43453: netfilter: nft_set_pipapo: fix stack out-of-bounds read in pipapo_drop()

Status: published. Published: 2026-05-08. Updated: 2026-11-06.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < 1957e793196e7f8557374fd4eda53abcbb42e1c0 (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < 57fb87ca095d5127cd7a27583b8ec43dcf7c9e9e (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < 60c1d18781e37bfb96290b86510eb01c5fa24d75 (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < 0a55d62cdb628923d8a21724374a70c76ac7d19d (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < dfbdac719198778b581bc0dd055df2542edb8c62 (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < e047f6fbb975f685d6c9fcef95b3b7787a79b46d (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < 324b749aa5b2d516ccfab933df9d3f56e7807f5f (affected, git); ≥ 3c4287f62044a90e73a561aa05fc46e62da173da; < d6d8cd2db236a9dd13dbc2d05843b3445cc964b5 (affected, git). Source: CNA: Linux
- Linux / Linux: 5.6 (affected); ≥ 0; < 5.6 (unaffected, semver); ≥ 5.10.253; ≤ 5.10.* (unaffected, semver); ≥ 5.15.203; ≤ 5.15.* (unaffected, semver); ≥ 6.1.167; ≤ 6.1.* (unaffected, semver); ≥ 6.6.130; ≤ 6.6.* (unaffected, semver); ≥ 6.12.78; ≤ 6.12.* (unaffected, semver); ≥ 6.18.19; ≤ 6.18.* (unaffected, semver); ≥ 6.19.9; ≤ 6.19.* (unaffected, semver); ≥ 7.0; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-06; percentile 2.29%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/1957e793196e7f8557374fd4eda53abcbb42e1c0 (CNA: Linux)

- https://git.kernel.org/stable/c/57fb87ca095d5127cd7a27583b8ec43dcf7c9e9e (CNA: Linux)

- https://git.kernel.org/stable/c/60c1d18781e37bfb96290b86510eb01c5fa24d75 (CNA: Linux)

- https://git.kernel.org/stable/c/0a55d62cdb628923d8a21724374a70c76ac7d19d (CNA: Linux)

- https://git.kernel.org/stable/c/dfbdac719198778b581bc0dd055df2542edb8c62 (CNA: Linux)

- https://git.kernel.org/stable/c/e047f6fbb975f685d6c9fcef95b3b7787a79b46d (CNA: Linux)

- https://git.kernel.org/stable/c/324b749aa5b2d516ccfab933df9d3f56e7807f5f (CNA: Linux)

- https://git.kernel.org/stable/c/d6d8cd2db236a9dd13dbc2d05843b3445cc964b5 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-43453; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-43453; retrieved 2026-11-06; source updated Not reported

Revision: bfb2dd30e30884e63a49f9d3c8a8d781b0e278728ebed6f163b0b95fe74843b5

Canonical: https://y2.dev/cve/CVE-2026-43453

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