CVE-2026-74653serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx
- —Not scoredno CVSS score yet
- 0.17%Exploitation in 30 daysEPSS · top 94% 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: serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx The NXP LPC32xx UART (PORT_LPC3220) can latch an RX character-timeout interrupt while the RX FIFO is empty: IIR reports UART_IIR_RX_TIMEOUT (0x0c) but LSR.DR is clear. A character timeout is only cleared by reading RHR, but serial8250_rx_chars() reads RHR only when LSR.DR is set, so nothing ever clears the condition. The interrupt is level-triggered and re-fires immediately, so on a single-core ARM926 the resulting interrupt storm livelocks the CPU. It is reproducible when userspace repeatedly opens the front-panel port (ttyS1): serial8250_do_set_termios() re-enables interrupts on unlock and the handler then spins forever with iir=0xcc lsr=0x60 ier=0x05, tripping the soft-lockup detector in serial8250_handle_irq_locked(). LPC32xx has no dedicated 8250 glue driver, it's driven by the generic 8250_of. Add a hardware specific handle_irq for PORT_LPC3220, wired up in of_platform_serial_setup() the same way fsl8250_handle_irq is installed. The handler follows dw8250_handle_irq(): on an RX timeout with an empty FIFO (LSR.DR and LSR.BI clear) it does one throwaway RHR read to clear the condition, then calls serial8250_handle_irq_locked(). No real received data is ever discarded, and it is a no-op on healthy UARTs which never report a timeout with DR clear. This is the same class of bug already worked around in other 8250 drivers; see commit 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt") which reports the identical iir=0xcc/lsr=0x60. See also UART_RX_TIMEOUT_QUIRK in 8250_omap, and the note in 8250_bcm7271.
Timeline
ID reserved
By Linux
- 7 days later
· 7 days later
Published
- 2 months later
· 2 months 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)
- 0.17% · top 94% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected e6e912c4964ce5976e508881207dfa96d5f856d7 – < cc325ce1c40a111824827532ac132afb3d1c342b
- affected e6e912c4964ce5976e508881207dfa96d5f856d7 – < c321dc5172c8c66e21ffbeeb7a2ebb88ae6fd4c3
- affected e6e912c4964ce5976e508881207dfa96d5f856d7 – < 3ce24bc4d115336218e59b7e286fd3a79f4fc4c6
- affected e6e912c4964ce5976e508881207dfa96d5f856d7 – < 7795e8abedc86438cae0454602cbf9038b94bf38
- affected e6e912c4964ce5976e508881207dfa96d5f856d7 – < 1423415471274abda87024967d7fe2206ceee0ea
- affected 2.6.36
- unaffected < 2.6.36
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.106 – ≤ 6.12.*
- unaffected 6.18.45 – ≤ 6.18.*
- unaffected 7.1.9 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References5
- https://git.kernel.org/stable/c/cc325ce1c40a111824827532ac132afb3d1c342b (opens in a new tab)
- https://git.kernel.org/stable/c/c321dc5172c8c66e21ffbeeb7a2ebb88ae6fd4c3 (opens in a new tab)
- https://git.kernel.org/stable/c/3ce24bc4d115336218e59b7e286fd3a79f4fc4c6 (opens in a new tab)
- https://git.kernel.org/stable/c/7795e8abedc86438cae0454602cbf9038b94bf38 (opens in a new tab)
- https://git.kernel.org/stable/c/1423415471274abda87024967d7fe2206ceee0ea (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-2026-64590 (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)
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[](https://cveledger.app/cve/CVE-2026-74653)Record last updated .