TTY port in Linux kernel skips I/O error flag on activation failure
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 6 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel tty_port code, from 2.6.33 before the fixed stable releases, does not restore the TTY_IO_ERROR flag when port activation fails. This allows I/O on a port that is gone or powered down. A TTY ioctl racing with hangup and open can cause a kernel panic or a NULL-pointer dereference.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: tty: tty_port: restore TTY_IO_ERROR on activation failure Make sure to restore the TTY_IO_ERROR flag if activation fails to prevent I/O attempts on a port that is gone or powered down. This specifically avoids issues like kernel panic due to unclocked accesses or NULL-pointer dereferences when accessing powered down or deregistered ports when a TTY ioctl races with hangup and open. Note that the flag is set again in tty_port_close() but not restoring it on activation failure leaves a window where drivers fail to handle the ioctl-hangup race.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.33 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.33 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 Patch available CNA
Remediation
Update the Linux kernel to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10 or 7.3 or later for the matching branch. Red Hat Enterprise Linux 7, 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 are affected. The sources list no fixed version for them.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98753
- 2026-10-18 Alias added: GHSA-fxvh-5c26-7p3q
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@16032c980d8f71642fcdc99309c571df3fcf3328, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score added · Red Hat
- 2026-10-30 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@5469dc4153a60289c5bae00215947c6ce09fcc0e +3 · CNA
- 2026-10-30 3 new references · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/761e8c5eb13d1b5e196b0b39bdfed6fc67af9dd2
- https://git.kernel.org/stable/c/5469dc4153a60289c5bae00215947c6ce09fcc0e
- https://git.kernel.org/stable/c/e24625bff786fa3f22cc38b5038362b910621e83
- https://git.kernel.org/stable/c/16032c980d8f71642fcdc99309c571df3fcf3328
- https://git.kernel.org/stable/c/34d4f67472ef7a744970b772a8565ddc727788e2
- https://git.kernel.org/stable/c/7021acc84c2e0add77a1a33152e3a1e428fdbfdb
- https://git.kernel.org/stable/c/6388409b711eb91b14fa075a4d861ccc4df1cfe7
- https://git.kernel.org/stable/c/56964f6a31238fb41d5830bb42520c5b10ff7d8f
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Sources
- CVE-2026-98753 · CVE Program
- CVE-2026-98753 · NVD
- FIRST EPSS
- GHSA-fxvh-5c26-7p3q · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98753 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences