CVE-2026-90088
Bluetooth: RFCOMM: Validate MTU in rfcomm_apply_pn() to prevent infinite loop
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Validate MTU in rfcomm_apply_pn() to prevent infinite loop rfcomm_apply_pn() accepts the MTU value from a remote PN (Parameter Negotiation) frame without checking for zero. When the remote peer sends an MTU of zero, d->mtu is set to 0. This causes the sendmsg path to enter an infinite loop when fragmenting data, as each fragment has size == min_t(size_t, len, 0) == 0, so the remaining length never decreases. The infinite allocation of zero-length skbs exhausts all system memory. Fix by clamping d->mtu to RFCOMM_DEFAULT_MTU when the negotiated value is zero, consistent with the initial value assigned in rfcomm_dlc_alloc().
INFO
Published Date :
Sept. 17, 2026, 5:16 p.m.
Last Modified :
Sept. 17, 2026, 5:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to include the fix.
- Ensure MTU values are validated in rfcomm_apply_pn.
- Clamp zero MTU values to RFCOMM_DEFAULT_MTU.
- Monitor system memory usage.
References to Advisories, Solutions, and Tools
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CVE-2026-90088.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-90088 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-90088
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 17, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Validate MTU in rfcomm_apply_pn() to prevent infinite loop rfcomm_apply_pn() accepts the MTU value from a remote PN (Parameter Negotiation) frame without checking for zero. When the remote peer sends an MTU of zero, d->mtu is set to 0. This causes the sendmsg path to enter an infinite loop when fragmenting data, as each fragment has size == min_t(size_t, len, 0) == 0, so the remaining length never decreases. The infinite allocation of zero-length skbs exhausts all system memory. Fix by clamping d->mtu to RFCOMM_DEFAULT_MTU when the negotiated value is zero, consistent with the initial value assigned in rfcomm_dlc_alloc(). Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90088.json">CVE-2026-90088</a> Added Reference https://git.kernel.org/stable/c/3988cbb1be501dbff909a2ee024670e3c955a66d Added Reference https://git.kernel.org/stable/c/44c98fd082eafd49d55a8a4077ff488175b2fe24 Added Reference https://git.kernel.org/stable/c/9b2e5f1928c99224345a9ed8c5dae5fc74964d6d Added Reference https://git.kernel.org/stable/c/aeee917a4878af95f0c63e18c5f22eaf6299c7b8 Added Reference https://git.kernel.org/stable/c/cbc2962da99b6b89345267d3aa74b4b573340548 Added Reference https://git.kernel.org/stable/c/e7c0aa45ae6c5a338661b23812bfcdef50bf3e96 Added Reference https://git.kernel.org/stable/c/f561e44261344adadf9d6a6dff31e3af9776d5c6 Added Reference https://git.kernel.org/stable/c/fc4851ff8dfb505e9a19efcc286712132bbd178d