# CVE-2025-38198: fbcon: Make sure modelist not set on unregistered console

Status: published. Published: 2025-07-04. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

fbcon: Make sure modelist not set on unregistered console

It looks like attempting to write to the "store_modes" sysfs node will
run afoul of unregistered consoles:

UBSAN: array-index-out-of-bounds in drivers/video/fbdev/core/fbcon.c:122:28
index -1 is out of range for type 'fb_info *[32]'
...
 fbcon_info_from_console+0x192/0x1a0 drivers/video/fbdev/core/fbcon.c:122
 fbcon_new_modelist+0xbf/0x2d0 drivers/video/fbdev/core/fbcon.c:3048
 fb_new_modelist+0x328/0x440 drivers/video/fbdev/core/fbmem.c:673
 store_modes+0x1c9/0x3e0 drivers/video/fbdev/core/fbsysfs.c:113
 dev_attr_store+0x55/0x80 drivers/base/core.c:2439

static struct fb_info *fbcon_registered_fb[FB_MAX];
...
static signed char con2fb_map[MAX_NR_CONSOLES];
...
static struct fb_info *fbcon_info_from_console(int console)
...
        return fbcon_registered_fb[con2fb_map[console]];

If con2fb_map contains a -1 things go wrong here. Instead, return NULL,
as callers of fbcon_info_from_console() are trying to compare against
existing "info" pointers, so error handling should kick in correctly.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 409d6c95f9c68bb7046410a3502e26e454a1e636; < b3237d451bf3a4490cb1a76f3b7c91d9888f1c4b (affected, git); ≥ 409d6c95f9c68bb7046410a3502e26e454a1e636; < 519ba75728ee8cd561dce25fc52a2ec5c47171dc (affected, git); ≥ 409d6c95f9c68bb7046410a3502e26e454a1e636; < f28f1f578cd810779d01999c60618cda14c281dd (affected, git); ≥ 409d6c95f9c68bb7046410a3502e26e454a1e636; < 54b28f7c567dd659e5f9562f518e4d7f3f6a367b (affected, git); ≥ 409d6c95f9c68bb7046410a3502e26e454a1e636; < cedc1b63394a866bf8663a3e40f4546f1d28c8d8 (affected, git). Source: CNA: Linux
- Linux / Linux: 5.19 (affected); ≥ 0; < 5.19 (unaffected, semver); ≥ 6.1.142; ≤ 6.1.* (unaffected, semver); ≥ 6.6.95; ≤ 6.6.* (unaffected, semver); ≥ 6.12.35; ≤ 6.12.* (unaffected, semver); ≥ 6.15.4; ≤ 6.15.* (unaffected, semver); ≥ 6.16; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.19% as of 2026-11-05; percentile 8.53%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/b3237d451bf3a4490cb1a76f3b7c91d9888f1c4b (CNA: Linux)

- https://git.kernel.org/stable/c/519ba75728ee8cd561dce25fc52a2ec5c47171dc (CNA: Linux)

- https://git.kernel.org/stable/c/f28f1f578cd810779d01999c60618cda14c281dd (CNA: Linux)

- https://git.kernel.org/stable/c/54b28f7c567dd659e5f9562f518e4d7f3f6a367b (CNA: Linux)

- https://git.kernel.org/stable/c/cedc1b63394a866bf8663a3e40f4546f1d28c8d8 (CNA: Linux)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (ADP: CVE)

- https://cert-portal.siemens.com/productcert/html/ssa-082556.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2025-38198; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-38198; retrieved 2026-11-05; source updated Not reported

Revision: 4801dfb3cdaa5d4485f9c05fdce9528b550cf7e0e6362c0ffe586489dfba9bc3

Canonical: https://y2.dev/cve/CVE-2025-38198

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