Vulnary
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Critical· 9.8official fix available

CVE-2025-39682

A flaw in the Linux kernel’s TLS handling can cause problems when a zero‑length record is processed. The bug can lead to improper record type handling, potentially allowing an attacker to disrupt the TLS connection. The issue has been fixed in newer kernel releases.

publishedSep 5, 2025
last modifiedJul 30, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
8th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 29, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Linux kernel 6.17 and earlier, including Debian 11.0. System administrators running affected kernel versions are at risk.

02

Real-world impact

An attacker could exploit the flaw to cause a denial‑of‑service by crashing the TLS stack or to manipulate the connection, potentially leading to loss of confidentiality, integrity, or availability of data.

03

Why this severity

The CVSS score of 9.8 reflects that the vulnerability allows an attacker to fully compromise confidentiality, integrity, and availability of the system without needing authentication or user interaction.

04

What to do about it

official fix available
recommended steps
  1. 011. Verify your current kernel version using `uname -r`.
  2. 022. Update your system to the latest kernel package available from your distribution’s repositories. For Debian, run `apt update && apt upgrade linux-image-<latest-version>`.
  3. 033. Reboot the system to load the new kernel.

NVD-referenced vendor advisory

05

Timeline

  1. Sep 5, 2025 · Sep 5, 2025
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 30, 2026 · 6h ago
    Advisory updated
    The NVD record was last revised.
  3. Jul 30, 2026 · 3h ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →