CVE-2026-90088: Bluetooth: RFCOMM: Validate MTU in rfcomm_apply_pn() to prevent infinite loop
Bluetooth: RFCOMM: Validate MTU in rfcommapplypn() to prevent infinite loop
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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Fixed in 6.6.157.1-1 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 5.10.270 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.1.188 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.190-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Configuration
Clamp d->mtu to RFCOMM_DEFAULT_MTU when the negotiated MTU value is zero in rfcomm_apply_pn().
Linux kernel Bluetooth RFCOMM d->mtu = RFCOMM_DEFAULT_MTU
Event History
Frequently Asked Questions
What does an attacker need to trigger the issue?
The attacker must act as a remote Bluetooth RFCOMM peer and send a Parameter Negotiation frame with an MTU value of zero. The vulnerable system must then use the affected RFCOMM sendmsg fragmentation path.
What is the operational impact of successful exploitation?
Sending with the negotiated zero MTU causes fragmentation to make no progress, repeatedly allocating zero-length skbs. This can exhaust all system memory.