CVE-2026-31498 (GCVE-0-2026-31498)
Vulnerability from cvelistv5
Published
2026-04-22 13:54
Modified
2026-04-22 13:54
Severity ?
VLAI Severity ?
EPSS score ?
Summary
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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 96298f640104e4cd9a913a6e50b0b981829b94ff Version: 4ad03ff6f680681c5f78254e37c4c856fa953629 Version: b7d0ca715c1008acd2fc018f02a56fed88f78b75 Version: 799263eb37a4f7f6d39334046929c3bc92452a7f Version: 8828622fb9b4201eeb0870587052e3d834cfaf61 Version: b432ea85ab8472763870dd0f2c186130dd36d68c |
||
{
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"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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"cpeApplicability": [
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix ERTM re-init and zero pdu_len infinite loop\n\nl2cap_config_req() processes CONFIG_REQ for channels in BT_CONNECTED\nstate to support L2CAP reconfiguration (e.g. MTU changes). However,\nsince both CONF_INPUT_DONE and CONF_OUTPUT_DONE are already set from\nthe initial configuration, the reconfiguration path falls through to\nl2cap_ertm_init(), which re-initializes tx_q, srej_q, srej_list, and\nretrans_list without freeing the previous allocations and sets\nchan-\u003esdu to NULL without freeing the existing skb. This leaks all\npreviously allocated ERTM resources.\n\nAdditionally, l2cap_parse_conf_req() does not validate the minimum\nvalue of remote_mps derived from the RFC max_pdu_size option. A zero\nvalue propagates to l2cap_segment_sdu() where pdu_len becomes zero,\ncausing the while loop to never terminate since len is never\ndecremented, exhausting all available memory.\n\nFix the double-init by skipping l2cap_ertm_init() and\nl2cap_chan_ready() when the channel is already in BT_CONNECTED state,\nwhile still allowing the reconfiguration parameters to be updated\nthrough l2cap_parse_conf_req(). Also add a pdu_len zero check in\nl2cap_segment_sdu() as a safeguard."
}
],
"providerMetadata": {
"dateUpdated": "2026-04-22T13:54:19.714Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/9760b83cfd24b38caee663f429011a0dd6064fa9"
},
{
"url": "https://git.kernel.org/stable/c/de37e2655b7abc3f59254c6b72256840f39fc6d5"
},
{
"url": "https://git.kernel.org/stable/c/e7aab23b7df89a3d754a5f0a7d2237548b328bd0"
},
{
"url": "https://git.kernel.org/stable/c/52667c859fe33f70c2e711cb81bbd505d5eb8e75"
},
{
"url": "https://git.kernel.org/stable/c/9a21a631ee034b1573dce14b572a24943dbfd7ae"
},
{
"url": "https://git.kernel.org/stable/c/900e4db5385ec2cacd372345a80ab9c8e105b3a3"
},
{
"url": "https://git.kernel.org/stable/c/042e2cd4bb11e5313b19b87593616524949e4c52"
},
{
"url": "https://git.kernel.org/stable/c/25f420a0d4cfd61d3d23ec4b9c56d9f443d91377"
}
],
"title": "Bluetooth: L2CAP: Fix ERTM re-init and zero pdu_len infinite loop",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31498",
"datePublished": "2026-04-22T13:54:19.714Z",
"dateReserved": "2026-03-09T15:48:24.103Z",
"dateUpdated": "2026-04-22T13:54:19.714Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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