CVE-2025-39686comedi: Make insn_rw_emulate_bits() do insn->n samples
- 7.8HighCVSS base score
- 0.20%Exploitation in 30 daysEPSS · top 91% 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: comedi: Make insn_rw_emulate_bits() do insn->n samples The `insn_rw_emulate_bits()` function is used as a default handler for `INSN_READ` instructions for subdevices that have a handler for `INSN_BITS` but not for `INSN_READ`. Similarly, it is used as a default handler for `INSN_WRITE` instructions for subdevices that have a handler for `INSN_BITS` but not for `INSN_WRITE`. It works by emulating the `INSN_READ` or `INSN_WRITE` instruction handling with a constructed `INSN_BITS` instruction. However, `INSN_READ` and `INSN_WRITE` instructions are supposed to be able read or write multiple samples, indicated by the `insn->n` value, but `insn_rw_emulate_bits()` currently only handles a single sample. For `INSN_READ`, the comedi core will copy `insn->n` samples back to user-space. (That triggered KASAN kernel-infoleak errors when `insn->n` was greater than 1, but that is being fixed more generally elsewhere in the comedi core.) Make `insn_rw_emulate_bits()` either handle `insn->n` samples, or return an error, to conform to the general expectation for `INSN_READ` and `INSN_WRITE` handlers.
Timeline
ID reserved
By Linux
- 5 months later
· 5 months later
Published
- 8 months later
· 8 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
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 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)
- 0.20% · top 91% 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 ed9eccbe8970f6eedc1b978c157caf1251a896d4 – < ab77e85bd3bc006ef40738f26f446a660813da44
- affected ed9eccbe8970f6eedc1b978c157caf1251a896d4 – < ae8bc1f07bcb31b8636420e03d1f9c3df6219a2b
- affected ed9eccbe8970f6eedc1b978c157caf1251a896d4 – < 842f307a1d115b24f2bcb2415c4e344f11f55930
- affected ed9eccbe8970f6eedc1b978c157caf1251a896d4 – < 92352ed2f9ac422181e381c2430c2d0dfb46faa0
- affected ed9eccbe8970f6eedc1b978c157caf1251a896d4 – < dc0a2f142d655700db43de90cb6abf141b73d908
- affected ed9eccbe8970f6eedc1b978c157caf1251a896d4 – < 7afba9221f70d4cbce0f417c558879cba0eb5e66
- affected 2.6.29
- unaffected < 2.6.29
- unaffected 5.15.190 – ≤ 5.15.*
- unaffected 6.1.149 – ≤ 6.1.*
- unaffected 6.6.103 – ≤ 6.6.*
- unaffected 6.12.44 – ≤ 6.12.*
- unaffected 6.16.4 – ≤ 6.16.*
- unaffected 6.17 – ≤ *
References
References8
- https://git.kernel.org/stable/c/ab77e85bd3bc006ef40738f26f446a660813da44 (opens in a new tab)
- https://git.kernel.org/stable/c/ae8bc1f07bcb31b8636420e03d1f9c3df6219a2b (opens in a new tab)
- https://git.kernel.org/stable/c/842f307a1d115b24f2bcb2415c4e344f11f55930 (opens in a new tab)
- https://git.kernel.org/stable/c/92352ed2f9ac422181e381c2430c2d0dfb46faa0 (opens in a new tab)
- https://git.kernel.org/stable/c/dc0a2f142d655700db43de90cb6abf141b73d908 (opens in a new tab)
- https://git.kernel.org/stable/c/7afba9221f70d4cbce0f417c558879cba0eb5e66 (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html (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-2025-31538 (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)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-39686)Record last updated .