CVE-2025-38685
Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix vmalloc out-of-bounds write in fast_imageblit This issue triggers when a userspace program does an ioctl FBIOPUT_CON2FBMAP by passing console number and frame buffer number. Ideally this maps console to frame buffer and updates the screen if console is visible. As part of mapping it has to do resize of console according to frame buffer info. if this resize fails and returns from vc_do_resize() and continues further. At this point console and new frame buffer are mapped and sets display vars. Despite failure still it continue to proceed updating the screen at later stages where vc_data is related to previous frame buffer and frame buffer info and display vars are mapped to new frame buffer and eventully leading to out-of-bounds write in fast_imageblit(). This bheviour is excepted only when fg_console is equal to requested console which is a visible console and updates screen with invalid struct references in fbcon_putcs().
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 6.1.153-1 |
| debian | forky | fixed | 6.16.3-1 |
| debian | sid | fixed | 6.16.3-1 |
| debian | trixie | fixed | 6.12.43-1 |
| debian | bullseye | fixed | 6.1.153-1~deb11u1 |
| linux-kernel | affected | 5.15.190 | |
| linux-kernel | 2.6.12 | affected | |
| debian | 11.0 | affected | |
References
- https://git.kernel.org/stable/c/078e62bffca4b7e72e8f3550eb063ab981c36c7a
- https://git.kernel.org/stable/c/27b118aebdd84161c8ff5ce49d9d536f2af10754
- https://git.kernel.org/stable/c/4c4d7ddaf1d43780b106bedc692679f965dc5a3a
- https://git.kernel.org/stable/c/56701bf9eeb63219e378cb7fcbd066ea4eaeeb50
- https://git.kernel.org/stable/c/af0db3c1f898144846d4c172531a199bb3ca375d
- https://git.kernel.org/stable/c/cfec17721265e72e50cc69c6004fe3475cd38df2
- https://git.kernel.org/stable/c/ed9b8e5016230868c8d813d9179523f729fec8c6
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://www.suse.com/security/cve/CVE-2025-38685.html
- https://security-tracker.debian.org/tracker/CVE-2025-38685
CWEs
CWE-787
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.