CVE-2026-31772 (GCVE-0-2026-31772)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-11 22:15
VLAI?
Title
Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync hci_le_big_create_sync() uses DEFINE_FLEX to allocate a struct hci_cp_le_big_create_sync on the stack with room for 0x11 (17) BIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31) entries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller hci_conn_big_create_sync(). When conn->num_bis is between 18 and 31, the memcpy that copies conn->bis into cp->bis writes up to 14 bytes past the stack buffer, corrupting adjacent stack memory. This is trivially reproducible: binding an ISO socket with bc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will eventually trigger hci_le_big_create_sync() from the HCI command sync worker, causing a KASAN-detectable stack-out-of-bounds write: BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0 Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71 Fix this by changing the DEFINE_FLEX count from the incorrect 0x11 to HCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that conn->bis can actually carry.
Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 91d19383b7ed035e22165ae5c836e50bb9f95fbe , < f5d446624345d309e7a4a1b27ea9f028d6a8c5d9 (git)
Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < aba0aea354015794e8312dd7efe726967e58aefe (git)
Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < eaf32002ca7b1ba51c9f140991fd9febe6de79f0 (git)
Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < bc39a094730ce062fa034a529c93147c096cb488 (git)
Affected: 8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd (git)
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Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (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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}


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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

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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.



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