CVE-2026-53403 — fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var
In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var info->var, a framebuffer's current mode, is expected to have a matching entry in info->modelist. var_to_display() relies on this and treats a failed fb_match_mode() as "This should not happen". fb_set_var() keeps it true by adding the mode to the list on every change, and do_register_framebuffer() does the same at registration. store_modes() replaces the modelist from userspace. fb_new_modelist() validates the new modes but does not check that info->var still has a match. It relies on fbcon_new_modelist() to re-point consoles, but that only handles consoles mapped to the framebuffer. With fbcon unbound there are none, so info->var is left describing a mode that is no longer in the list. A later console takeover runs var_to_display(), where fb_match_mode() returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it to display_to_var(), and fb_videomode_to_var() dereferences the NULL mode. Keep the current mode in the list in fb_new_modelist(), the same way fb_set_var() does.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 2.6.12≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 7f08fc10fa3d3366dc3af723970bd03d7d6d10e3≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 88913059c77e171f44ba829282d42dde0d458811≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < eea16b6f805c0b1fb2f72f0f771088ea45356956≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 7640b4f68acb54c2c4f6b4a8aee0e9849dacd929≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 0d8c7f21ad8529d5c181e61f86be35b887ae2e4d≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 8707f02ac9f5f632039b60df2c9f3dc914709f72 and 1 more≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 1458a4d804550b7101e8bb02c1cb941088e4c0c7 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
version 2.6.12-rc4version 2.6.12-rc5≥ 2.6.12.1 and < 5.10.260version 2.6.12-rc3version 2.6.12-rc2version 2.6.12≥ 6.19 and < 7.1.3≥ 6.13 and < 6.18.38 and 4 more≥ 6.7 and < 6.12.95≥ 6.2 and < 6.6.144≥ 5.16 and < 6.1.177≥ 5.11 and < 5.15.211 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.5 | CVSS 3.1 | Medium | 1.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 5.5
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
8 on the record
- git.kernel.org/stable/c/0d8c7f21ad8529d5c181e61f86be35b887ae2e4d
- git.kernel.org/stable/c/7f08fc10fa3d3366dc3af723970bd03d7d6d10e3
- git.kernel.org/stable/c/1458a4d804550b7101e8bb02c1cb941088e4c0c7
- git.kernel.org/stable/c/88913059c77e171f44ba829282d42dde0d458811
- git.kernel.org/stable/c/7640b4f68acb54c2c4f6b4a8aee0e9849dacd929
- git.kernel.org/stable/c/4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e
- git.kernel.org/stable/c/eea16b6f805c0b1fb2f72f0f771088ea45356956
- git.kernel.org/stable/c/8707f02ac9f5f632039b60df2c9f3dc914709f72
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 11h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 11h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-53403 is "fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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