CVE-2026-63883
- Source
- https://cve.org/CVERecord?id=CVE-2026-63883
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63883.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-63883
- Downstream
- Related
- Published
- 2026-07-19T14:54:56Z
- Modified
- 2026-08-27T18:26:09Z
- Severity
-
- 7.3 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L CVSS Calculator
- Summary
- serial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
serial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ
When uart_flush_buffer() runs before the DMA completion IRQ is delivered, the following race can occur (all steps serialized by uart_port_lock):
- DMA starts: tx_remaining = N, kfifo contains N bytes
- DMA completes in hardware; IRQ is pending but not yet delivered
- uart_flush_buffer() acquires the port lock and calls kfifo_reset(), making kfifo_len() = 0 while tx_remaining remains N
- uart_flush_buffer() releases the port lock
- DMA IRQ fires; handle_tx_dma() acquires the port lock and calls uart_xmit_advance(uport, tx_remaining) on an empty kfifo
uart_xmit_advance() increments kfifo->out by tx_remaining. Since kfifo_reset() already set both in and out to 0, out wraps past in, causing kfifo_len() to return UART_XMIT_SIZE - tx_remaining. The next start_tx_dma() call then submits a DMA transfer of stale buffer data.
Fix this by snapshotting kfifo_len() at the start of handle_tx_dma() and skipping uart_xmit_advance() when fifo_len < tx_remaining, which indicates the kfifo was reset by a preceding flush.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63883.json" }- References
-
- https://git.kernel.org/stable/c/0d2c41a8b00934ddf8a7c1b4cf72dffa1e629c46
- https://git.kernel.org/stable/c/452d6fa37ae9b021f4f6d397dbae077f7296f6f4
- https://git.kernel.org/stable/c/654f45a8569f3cd6ff20bd724a18e0cce65893ba
- https://git.kernel.org/stable/c/b1159dce10b38eb795e4c96cdc4d34b83cec81c5
- https://git.kernel.org/stable/c/c91ea13375f70f6271a0183445e34e83b8f4d8f7
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63883.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-63883
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2aaa43c7077833301c237684cd7bc9ae5e3dec95Fixedc91ea13375f70f6271a0183445e34e83b8f4d8f7Fixedb1159dce10b38eb795e4c96cdc4d34b83cec81c5Fixed654f45a8569f3cd6ff20bd724a18e0cce65893baFixed0d2c41a8b00934ddf8a7c1b4cf72dffa1e629c46Fixed452d6fa37ae9b021f4f6d397dbae077f7296f6f4