Vulnerability in Linux kernel (CVE-2026-98739)
Summary
Vulnerability in Linux kernel (CVE-2026-98739). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: Fix initial port reference race
For RFCOMM_RELEASE_ONHUP devices, rfcomm_tty_install() and
__rfcomm_release_dev() both use RFCOMM_TTY_OWNED to decide who drops the
initial tty_port reference. The release path tests the bit separately
from the install path setting it, so both can drop that reference.
The synchronous hangup does not prevent this race: port->tty is not
assigned until tty_port_open(), after installation. The following
interleaving is possible:
- Install and release each obtain a reference with rfcomm_dev_get().
- Release observes RFCOMM_TTY_OWNED clear.
- Install sets RFCOMM_TTY_OWNED and drops the initial reference.
- Release drops the same initial reference again.
- TTY cleanup drops its reference and frees the device.
- Release performs its final tty_port_put() on the freed port.
KASAN reported:
BUG: KASAN: slab-use-after-free in tty_port_put+0x22/0x190
Write of size 4 at addr ffff8881001d3d5c by task poc/92
Call Trace:
tty_port_put+0x22/0x190
rfcomm_dev_ioctl+0x1d4/0x1930
sock_do_ioctl+0x110/0x260
sock_ioctl+0x380/0x590
__x64_sys_ioctl+0x134/0x1c0
Allocated by task 88:
rfcomm_dev_ioctl+0x8f6/0x1930
sock_do_ioctl+0x110/0x260
sock_ioctl+0x380/0x590
__x64_sys_ioctl+0x134/0x1c0
Freed by task 65:
kfree+0x131/0x3c0
rfcomm_dev_destruct+0x23b/0x2f0
release_one_tty+0xc1/0x370
process_one_work+0x661/0x1090
U…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-98739 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-98739" on the vendor's site.
CVE-2026-98739 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-98739 linux
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com