CVE-2026-31684 (GCVE-0-2026-31684)

Vulnerability from cvelistv5 – Published: 2026-04-25 08:47 – Updated: 2026-06-01 16:13
VLAI
Title
net: sched: act_csum: validate nested VLAN headers
Summary
In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < 0410c619e86551677fb79887a38eccad3f5a0725 (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < 886469b6455611a511aa6013e957e15e50577513 (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < 46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09 (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2 (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < a69738efea0996d05a3c7d2178551b891744df1b (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < ec4930979b3f7bbeb7af5744599fc6603a4dba62 (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < 3d165d975305cf76ff0b10a3c798fb31e5f5f9a5 (git)
Affected: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 , < c842743d073bdd683606cb414eb0ca84465dd834 (git)
Affected: 3764bfae5056e95617b6ee074129297e11710886 (git)
Affected: 4.19.99 , < 4.20 (semver)
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Linux Linux Affected: 5.1
Unaffected: 0 , < 5.1 (semver)
Unaffected: 5.10.258 , ≤ 5.10.* (semver)
Unaffected: 5.15.209 , ≤ 5.15.* (semver)
Unaffected: 6.1.175 , ≤ 6.1.* (semver)
Unaffected: 6.6.136 , ≤ 6.6.* (semver)
Unaffected: 6.12.83 , ≤ 6.12.* (semver)
Unaffected: 6.18.24 , ≤ 6.18.* (semver)
Unaffected: 6.19.14 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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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.