CVE-2026-43026 (GCVE-0-2026-43026)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-11 22:16
VLAI?
Title
netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent ctnetlink_alloc_expect() allocates expectations from a non-zeroing slab cache via nf_ct_expect_alloc(). When CTA_EXPECT_NAT is not present in the netlink message, saved_addr and saved_proto are never initialized. Stale data from a previous slab occupant can then be dumped to userspace by ctnetlink_exp_dump_expect(), which checks these fields to decide whether to emit CTA_EXPECT_NAT. The safe sibling nf_ct_expect_init(), used by the packet path, explicitly zeroes these fields. Zero saved_addr, saved_proto and dir in the else branch, guarded by IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when NAT is enabled. Confirmed by priming the expect slab with NAT-bearing expectations, freeing them, creating a new expectation without CTA_EXPECT_NAT, and observing that the ctnetlink dump emits a spurious CTA_EXPECT_NAT containing stale data from the prior allocation.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < a5a89db6981a1ddf2314bf50cb49db5a3146185f (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < 1c2ebdeff8d088a2e47ae25d7b38447249adace2 (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < a64b7bf84b4d5ea54218c5d374ec87fff9000f43 (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < 2898080c054ea4d6ddfaaf21bbedbc229a9a8376 (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < fd002ff2ea030cbfb0188a11b3c60ce7f84485f4 (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < 929f7a9a7aad9404a5867216c3f8738232355b38 (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36 (git)
Affected: 076a0ca02644657b13e4af363f487ced2942e9cb , < 35177c6877134a21315f37d57a5577846225623e (git)
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Linux Linux Affected: 3.4
Unaffected: 0 , < 3.4 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.134 , ≤ 6.6.* (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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    "dateReserved": "2026-05-01T14:12:55.976Z",
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.