CVE-2026-89725 is a vulnerability in Linux Kernel
Published on September 11, 2026
media: cec: stm32: prevent out-of-bounds write on RX overflow
In the Linux kernel, the following vulnerability has been resolved:
media: cec: stm32: prevent out-of-bounds write on RX overflow
stm32_rx_done() appends each received CEC byte to rx_msg.msg[] using
rx_msg.len as the write index, incrementing it on every RXBR
(receive-byte-ready) interrupt without checking it against the buffer
size:
cec->rx_msg.msg[cec->rx_msg.len++] = val & 0xFF;
rx_msg.msg[] is a fixed CEC_MAX_MSG_SIZE (16) byte array in struct
cec_msg, and rx_msg.len is only reset on RXACKE/RXOVR or after a
completed message (RXEND). The number of bytes received before RXEND is
decided by the remote CEC device (it sets EOM), not by the driver. A
peer that keeps sending bytes without ending the message drives RXBR
repeatedly, pushing rx_msg.len past 16 and writing peer-controlled bytes
out of bounds into the surrounding memory. This is reachable in normal
operation once the driver has probed and receiving is enabled, from the
IRQ thread, without any local privilege.
The length check in the CEC core runs on the consumer side, after the
byte has been stored, so it does not prevent the overflow. Bound the
index in the driver before the store, as the other platform CEC drivers
already do (e.g. tegra_cec), dropping the excess bytes of an overlong
frame.
Found by static analysis tool CodeQL.
Products Associated with CVE-2026-89725
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Affected Versions
Linux:- Version d69ae57453c80a2193bcdb3fd762efbec447eecf and below c3edd7fb8e3692423a702705509947fc9c30b3d1 is affected.
- Version d69ae57453c80a2193bcdb3fd762efbec447eecf and below 0c260d3f97e52978a8c769bb095ac0901333a3ac is affected.
- Version d69ae57453c80a2193bcdb3fd762efbec447eecf and below a85ce3b175615c2e13bc01e8a1b6b6b6910fde57 is affected.
- Version d69ae57453c80a2193bcdb3fd762efbec447eecf and below fb9dda38d4b9e90db07ed9a0ee2d35bf85494035 is affected.
- Version 4.13 is affected.
- Before 4.13 is unaffected.
- Version 6.12.109, <= 6.12.* is unaffected.
- Version 6.18.50, <= 6.18.* is unaffected.
- Version 7.2.4, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.