Vulnary
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Critical· 9.8official fix available

CVE-2026-63922

A critical flaw in the Linux kernel's IPv6 extension header handling could allow a remote, unauthenticated attacker to trigger memory corruption or a system crash. The kernel code has been fixed to refresh a cached network header pointer after processing the HAO option, preventing the bug. No known active exploitation or public exploit is documented.

publishedJul 19, 2026
last modifiedJul 28, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
49th 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 19, 2026

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

01

Who is affected

Users of the Linux kernel are potentially affected; no specific product versions are listed in the source data.

02

Real-world impact

If exploited, the vulnerability could lead to a crash or potential code execution on affected Linux systems processing malicious IPv6 traffic.

03

Why this severity

Critical (CVSS 9.8) means the issue is easy to exploit over a network without privileges and can severely compromise confidentiality, integrity, and availability.

04

What to do about it

official fix available
recommended steps
  1. 01Update the Linux kernel to a build that includes the code change described in the NVD entry: ipv6: exthdrs: refresh nh after handling HAO option.

NVD description states the vulnerability has been resolved in the Linux kernel; no CISA KEV required action.

05

Timeline

  1. Jul 19, 2026 · 14d ago
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 20, 2026 · 13d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
  3. Jul 28, 2026 · 5d ago
    Advisory updated
    The NVD record was last revised.
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 →