CVE-2026-53161misc: fastrpc: fix use-after-free of fastrpc_user in workqueue context
- 7.8HighCVSS base score
- 0.13%Exploitation in 30 daysEPSS · top 98% 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: misc: fastrpc: fix use-after-free of fastrpc_user in workqueue context There is a race between fastrpc_device_release() and the workqueue that processes DSP responses. When the user closes the file descriptor, fastrpc_device_release() frees the fastrpc_user structure. Concurrently, an in-flight DSP invocation can complete and fastrpc_rpmsg_callback() schedules context cleanup via schedule_work(&ctx->put_work). If the workqueue runs fastrpc_context_free() in parallel with or after fastrpc_device_release() has freed the user structure, it dereferences the freed fastrpc_user. Depending on the state of the context at the time of the race, any one of the following accesses can be hit: 1. fastrpc_buf_free() calls fastrpc_ipa_to_dma_addr(buf->fl->cctx, ...) to strip the SID bits from the stored IOVA before passing the physical address to dma_free_coherent(). 2. fastrpc_free_map() reads map->fl->cctx->vmperms[0].vmid to reconstruct the source permission bitmask needed for the qcom_scm_assign_mem() call that returns memory from the DSP VM back to HLOS. 3. fastrpc_free_map() acquires map->fl->lock to safely remove the map node from the fl->maps list. The resulting use-after-free manifests as: pc : fastrpc_buf_free+0x38/0x80 [fastrpc] lr : fastrpc_context_free+0xa8/0x1b0 [fastrpc] fastrpc_context_free+0xa8/0x1b0 [fastrpc] fastrpc_context_put_wq+0x78/0xa0 [fastrpc] process_one_work+0x180/0x450 worker_thread+0x26c/0x388 Add kref-based reference counting to fastrpc_user. Have each invoke context take a reference on the user at allocation time and release it when the context is freed. Release the initial reference in fastrpc_device_release() at file close. Move the teardown of the user structure — freeing pending contexts, maps, mmaps, and the channel context reference — into the kref release callback fastrpc_user_free(), so that it runs only when the last reference is dropped, regardless of whether that happens at device close or after the final in-flight context completes.
Timeline
ID reserved
By Linux
- 16 days later
· 16 days later
Published
- 41 days later
· 41 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
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.13% · top 98% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < c6e5c2be09f814377d7f1ce97370a5b7b3e02814
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < e1e3a05efe5954d5bad01157d79429d39a67a7ae
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < d42679eef34dd590b694ce3b666c5e2ba10cd4bf
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < df08fadcf0e5f3708365ec3b6d30b5aafd98bea1
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < ecea4967c2bff92c2fafbc59893f711b39f7b152
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < 5278ccd357e0d7aeeb1e76c0f3e0e02894a9897c
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < fbe0947420eec18a84638d29468c2d563ce4e6a3
- affected 6cffd79504ce040f460831030d3069fa1c99bb71 – < e85eb5feca8e254905ffa6c57a3c99c89a674a0f
- affected 5.1
- unaffected < 5.1
- unaffected 5.10.259 – ≤ 5.10.*
- unaffected 5.15.210 – ≤ 5.15.*
- unaffected 6.1.176 – ≤ 6.1.*
- unaffected 6.6.143 – ≤ 6.6.*
- unaffected 6.12.94 – ≤ 6.12.*
- unaffected 6.18.36 – ≤ 6.18.*
- unaffected 7.0.13 – ≤ 7.0.*
- unaffected 7.1 – ≤ *
References
References8
- https://git.kernel.org/stable/c/c6e5c2be09f814377d7f1ce97370a5b7b3e02814 (opens in a new tab)
- https://git.kernel.org/stable/c/e1e3a05efe5954d5bad01157d79429d39a67a7ae (opens in a new tab)
- https://git.kernel.org/stable/c/d42679eef34dd590b694ce3b666c5e2ba10cd4bf (opens in a new tab)
- https://git.kernel.org/stable/c/df08fadcf0e5f3708365ec3b6d30b5aafd98bea1 (opens in a new tab)
- https://git.kernel.org/stable/c/ecea4967c2bff92c2fafbc59893f711b39f7b152 (opens in a new tab)
- https://git.kernel.org/stable/c/5278ccd357e0d7aeeb1e76c0f3e0e02894a9897c (opens in a new tab)
- https://git.kernel.org/stable/c/fbe0947420eec18a84638d29468c2d563ce4e6a3 (opens in a new tab)
- https://git.kernel.org/stable/c/e85eb5feca8e254905ffa6c57a3c99c89a674a0f (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-2026-39252 (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-2026-53161)Record last updated .