Bluetooth: L2CAP: fix tx ident leak for commands without a response
Summary
| CVE | CVE-2026-72333 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-15 06:22:06 UTC |
| Updated | 2026-08-17 06:18:36 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix tx ident leak for commands without a response Commit 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident") changed ident allocation to use an IDA, releasing idents in l2cap_put_ident() when the matching response command is received. But identifiers allocated for commands that have no response defined are never released. In particular L2CAP_LE_CREDITS is sent repeatedly for the lifetime of an LE CoC channel, so a peer streaming data to the host exhausts the 1-255 ident range after 254 credit packets. From then on l2cap_get_ident() fails: kernel: Bluetooth: Unable to allocate ident: -28 and every subsequent L2CAP_LE_CREDITS packet is sent with ident 0, which is invalid (Core Spec, Vol 3, Part A, Section 4: "Signaling identifier 0x00 is an invalid identifier and shall never be used in any command"). Remote stacks that validate the ident drop these commands, never receive new credits, and the channel stalls permanently. With default socket buffers this happens after roughly 0.5 MB of received data (the exact amount depends on the socket receive buffer): < ACL Data TX: Handle 2048 flags 0x00 dlen 12 LE L2CAP: LE Flow Control Credit (0x16) ident 0 len 4 Source CID: 64 Credits: 1 Release the ident immediately after sending L2CAP_LE_CREDITS since no response will ever release it. Use a local variable instead of chan->ident so that an ident that an EXT_FLOWCTL channel may be waiting on (e.g. a pending reconfigure) is not overwritten by a credit packet. Also add the missing L2CAP_LE_CONN_RSP case to l2cap_put_ident() so idents allocated for outgoing L2CAP_LE_CONN_REQ commands are released when the response arrives. |
Risk And Classification
EPSS: 0.002090000 probability, percentile 0.113530000 (date 2026-08-17)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected e86554c37d3d2b4b24608e0313f882cae28b8adb b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6 git | Not specified |
| CNA | Linux | Linux | affected 9b24ad4787cad46a3917620799f8455c6533b8df bd1e01170341291292fd4c46b5f6949da282ca6c git | Not specified |
| CNA | Linux | Linux | affected ea6cf86167b3972caa68972d2a1ad43ecbbb8331 0c602cb8f148a36bfb39c25ade400bdadc023c4f git | Not specified |
| CNA | Linux | Linux | affected 6c3ea155e5ee3e56606233acde8309afda66d483 d0a2b0c81f112540a337cde1c20251bf05ddf1da git | Not specified |
| CNA | Linux | Linux | affected 6c3ea155e5ee3e56606233acde8309afda66d483 6e1930ece855a4c256f1c7e6632d634cfb9888b5 git | Not specified |
| CNA | Linux | Linux | affected ed97bb2cf96684ee646be6f37e4c4835f9d30caa git | Not specified |
| CNA | Linux | Linux | affected 84bc3197f7d87c5b89c156e853d0561a9154eceb git | Not specified |
| CNA | Linux | Linux | affected 8c1cdbc1bacc0cf9c27c3ebda11a81c3dcd01630 git | Not specified |
| CNA | Linux | Linux | affected 6.18.21 6.18.40 semver | Not specified |
| CNA | Linux | Linux | affected 5.10.261 5.11 semver | Not specified |
| CNA | Linux | Linux | affected 5.15.212 5.16 semver | Not specified |
| CNA | Linux | Linux | affected 6.19.11 6.20 semver | Not specified |
| CNA | Linux | Linux | affected 7.0 | Not specified |
| CNA | Linux | Linux | unaffected 7.0 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.40 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.5 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/6e1930ece855a4c256f1c7e6632d634cfb9888b5 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/d0a2b0c81f112540a337cde1c20251bf05ddf1da | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/bd1e01170341291292fd4c46b5f6949da282ca6c | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/0c602cb8f148a36bfb39c25ade400bdadc023c4f | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.