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

Vulnerability from cvelistv5 – Published: 2026-04-25 08:47 – Updated: 2026-05-23 16:05
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
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux 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: 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.