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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-31498

Bluetooth: L2CAP: Fix ERTM re-init and zero pdu_len infinite loop

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix ERTM re-init and zero pdu_len infinite loop l2cap_config_req() processes CONFIG_REQ for channels in BT_CONNECTED state to support L2CAP reconfiguration (e.g. MTU changes). However, since both CONF_INPUT_DONE and CONF_OUTPUT_DONE are already set from the initial configuration, the reconfiguration path falls through to l2cap_ertm_init(), which re-initializes tx_q, srej_q, srej_list, and retrans_list without freeing the previous allocations and sets chan->sdu to NULL without freeing the existing skb. This leaks all previously allocated ERTM resources. Additionally, l2cap_parse_conf_req() does not validate the minimum value of remote_mps derived from the RFC max_pdu_size option. A zero value propagates to l2cap_segment_sdu() where pdu_len becomes zero, causing the while loop to never terminate since len is never decremented, exhausting all available memory. Fix the double-init by skipping l2cap_ertm_init() and l2cap_chan_ready() when the channel is already in BT_CONNECTED state, while still allowing the reconfiguration parameters to be updated through l2cap_parse_conf_req(). Also add a pdu_len zero check in l2cap_segment_sdu() as a safeguard.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < 9760b83cfd24b38caee663f429011a0dd6064fa9affected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < de37e2655b7abc3f59254c6b72256840f39fc6d5affected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < e7aab23b7df89a3d754a5f0a7d2237548b328bd0affected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < 52667c859fe33f70c2e711cb81bbd505d5eb8e75affected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < 9a21a631ee034b1573dce14b572a24943dbfd7aeaffected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < 900e4db5385ec2cacd372345a80ab9c8e105b3a3affected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < 042e2cd4bb11e5313b19b87593616524949e4c52affected
  • 96298f640104e4cd9a913a6e50b0b981829b94ff to < 25f420a0d4cfd61d3d23ec4b9c56d9f443d91377affected
  • 4ad03ff6f680681c5f78254e37c4c856fa953629affected
  • b7d0ca715c1008acd2fc018f02a56fed88f78b75affected
  • 799263eb37a4f7f6d39334046929c3bc92452a7faffected
  • 8828622fb9b4201eeb0870587052e3d834cfaf61affected
  • b432ea85ab8472763870dd0f2c186130dd36d68caffected
  • 4.4.238 to < 4.5affected
  • 4.9.238 to < 4.10affected
  • 4.14.200 to < 4.15affected
  • 4.19.149 to < 4.20affected
  • 5.4.69 to < 5.5affected

Linux Linux

Default version status: affected

  • 5.7affected
  • 0 to < 5.7unaffected
  • 5.10.253 to ≤ 5.10.*unaffected
  • 5.15.203 to ≤ 5.15.*unaffected
  • 6.1.168 to ≤ 6.1.*unaffected
  • 6.6.131 to ≤ 6.6.*unaffected
  • 6.12.80 to ≤ 6.12.*unaffected
  • 6.18.21 to ≤ 6.18.*unaffected
  • 6.19.11 to ≤ 6.19.*unaffected
  • 7.0 to ≤ *unaffected

References