CVE-2026-72333

UnknownEPSS 0.21%

Last modified

CVE-2026-72333 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.21%

11.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= e86554c37d3d2b4b24608e0313f882cae28b8adb, < b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6; >= 9b24ad4787cad46a3917620799f8455c6533b8df, < bd1e01170341291292fd4c46b5f6949da282ca6c; >= ea6cf86167b3972caa68972d2a1ad43ecbbb8331, < 0c602cb8f148a36bfb39c25ade400bdadc023c4f; >= 6c3ea155e5ee3e56606233acde8309afda66d483, < d0a2b0c81f112540a337cde1c20251bf05ddf1da; >= 6c3ea155e5ee3e56606233acde8309afda66d483, < 6e1930ece855a4c256f1c7e6632d634cfb9888b5; ed97bb2cf96684ee646be6f37e4c4835f9d30caa; 84bc3197f7d87c5b89c156e853d0561a9154eceb; 8c1cdbc1bacc0cf9c27c3ebda11a81c3dcd01630; >= 6.18.21, < 6.18.40; >= 5.10.261, < 5.11; >= 5.15.212, < 5.16; >= 6.19.11, < 6.20
LinuxLinux7.0

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-72333?
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.
How severe is CVE-2026-72333?
Severity scoring for CVE-2026-72333 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-72333?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST