CVE-2026-98840 Vulnerability Analysis & Exploit Details

CVE-2026-98840
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-98840 Details

Status: Received on 18 Oct 2026, 16:17 UTC

Last updated: 🕐 21 Oct 2026, 13:21 UTC
Originally published on: 🕓 18 Oct 2026, 16:17 UTC

Time between publication and last update: 2 days

CVSS Release:

CVE-2026-98840 Vulnerability Summary

CVE-2026-98840: In the Linux kernel, the following vulnerability has been resolved: vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF The reload of 'vc' added by commit 8fb9ea65c9d1 ("vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF") sits after the 'if (ret)' block, so the copy-failure break path exits the loop without reloading vc. If the vc was kfree()'d via vc_port_destruct during the unlocked copy_from_user() window, the post-loop 'if (written && vc) vcs_scr_updated(vc)' is reached with a stale non-NULL vc. The '&& vc' guard from commit a287620312dc ("vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write") only handles the NULL case, not this stale-non-NULL case; vcs_notifier() then reads param->vc->vc_num from freed memory: BUG: KASAN: slab-use-after-free in vcs_notifier+0x7c/0xd0 Read of size 2 at addr ffff888007149190 Call Trace: vcs_notifier+0x7c/0xd0 atomic_notifier_call_chain+0x70/0xa0 vcs_scr_updated+0x77/0xa0 vcs_write+0x71b/0x7e0 Allocated by task: vc_allocate -> con_install -> tty_open Freed by task: kfree <- vt_ioctl (VT_DISALLOCATE -> vc_port_destruct) Move the reload to immediately after console_lock(), before 'if (ret)', so every break path below passes a fresh vc to the post-loop vcs_scr_updated().

Assessing the Risk of CVE-2026-98840

Access Complexity Graph

The exploitability of CVE-2026-98840 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-98840

No exploitability data is available for CVE-2026-98840.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-98840, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-98840, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-98840 does not compromise confidentiality.
  • Integrity: None
    CVE-2026-98840 does not impact data integrity.
  • Availability: None
    CVE-2026-98840 does not affect system availability.

CVE-2026-98840 References

External References

CWE Common Weakness Enumeration

Unknown

Protect Your Infrastructure against CVE-2026-98840: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2026-116119 – A vulnerability was found in NocoDB up to 2026.08.0. This affects an unknown part of the file packages/nocodb/src/services/users/users.service.ts o...
  • CVE-2026-116118 – A vulnerability has been found in Z.ai Zcode up to 3.14.3/3.15.1. Affected by this issue is some unknown functionality of the component Sed Command...
  • CVE-2026-116117 – A flaw has been found in halo-dev halo up to 2.27.0-beta.1. Affected by this vulnerability is the function run.halo.app.theme.DefaultViewNameResolv...
  • CVE-2026-113345 – Electronic delivery item Inspection Support System provided by Japan's Ministry of Land, Infrastructure, Transport and Tourism contains an improper...
  • CVE-2026-116116 – A vulnerability was detected in Yoosee GM8135S Camera 21.00.01.36. Affected is an unknown function of the component Secure Boot. Performing a manip...