CVE-2026-90193mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler
- —Not scoredno CVSS score yet
- 0.21%Exploitation in 30 daysEPSS · top 89% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler qcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding chan->lock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an rt_spinlock (rtmutex-based), which tracks ownership and can sleep. The callback chain triggered by mbox_chan_received_data() eventually reaches mailbox_clear_channel() -> mbox_send_message() -> add_to_rbuf(), which attempts to re-acquire the same chan->lock. Since rtmutex detects the re-entrant lock attempt by the same owner, the thread blocks waiting for a lock it already holds, causing a permanent deadlock. This deadlock manifests as 'irq/N-apss_cpucp_mbox' stuck in D state with the following call trace: rt_spin_lock -> mbox_send_message -> mailbox_clear_channel -> scmi_rx_callback -> mbox_chan_received_data [<- held chan->lock here] Fix by saving chan->cl locally and clearing the HW interrupt register inside the lock, then invoking mbox_chan_received_data() after releasing the lock. This preserves the mutual exclusion for chan->cl access while avoiding the lock re-entrancy that causes the PREEMPT_RT deadlock.
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 32 days later
· 32 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.21% · top 89% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 – < aa482273f32117c3adeba9b1cc945e0b5d33722d
- affected 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 – < 8b8de6400c86937ed57d680d06d716e167b381de
- affected 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 – < e40b3edeaf25cd09e9c88edb1ef99373ca37593b
- affected 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 – < 3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c
- affected 6.11
- unaffected < 6.11
- unaffected 6.12.110 – ≤ 6.12.*
- unaffected 6.18.52 – ≤ 6.18.*
- unaffected 7.2.6 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References4
- https://git.kernel.org/stable/c/aa482273f32117c3adeba9b1cc945e0b5d33722d (opens in a new tab)
- https://git.kernel.org/stable/c/8b8de6400c86937ed57d680d06d716e167b381de (opens in a new tab)
- https://git.kernel.org/stable/c/e40b3edeaf25cd09e9c88edb1ef99373ca37593b (opens in a new tab)
- https://git.kernel.org/stable/c/3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-81786 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-90193)Record last updated .