CVE-2025-39713
In the Linux kernel, the following vulnerability has been resolved: media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt() In the interrupt handler rain_interrupt(), the buffer full check on rain->buf_len is performed before acquiring…
Does this matter?
Lower severity and a low EPSS score (0.13%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt() In the interrupt handler rain_interrupt(), the buffer full check on rain->buf_len is performed before acquiring rain->buf_lock. This creates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as rain->buf_len is concurrently accessed and modified in the work handler rain_irq_work_handler() under the same lock. Multiple interrupt invocations can race, with each reading buf_len before it becomes full and then proceeding. This can lead to both interrupts attempting to write to the buffer, incrementing buf_len beyond its capacity (DATA_SIZE) and causing a buffer overflow. Fix this bug by moving the spin_lock() to before the buffer full check. This ensures that the check and the subsequent buffer modification are performed atomically, preventing the race condition. An corresponding spin_unlock() is added to the overflow path to correctly release the lock. This possible bug was found by an experimental static analysis tool developed by our team.
- CVSS 3.1
- 4.7 MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-367
- Affected
- linux/linux kernel · debian/debian linux
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1c2769dc80255824542ea5a4ff1a07dcdeb1603fPatch
- https://git.kernel.org/stable/c/2964dbe631fd21ad7873b1752b895548d3c12496Patch
- https://git.kernel.org/stable/c/3c3e33b7edca7a2d6a96801f287f9faeb684d655Patch
- https://git.kernel.org/stable/c/6aaef1a75985865d8c6c5b65fb54152060faba48Patch
- https://git.kernel.org/stable/c/7af160aea26c7dc9e6734d19306128cce156ec40Patch
- https://git.kernel.org/stable/c/ed905fe7cba03cf22ae0b84cf1b73cd1c070423aPatch
- https://git.kernel.org/stable/c/fbc81e78d75bf28972bc22b1599559557b1a1b83Patch
- https://git.kernel.org/stable/c/ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59Patch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.