Red Hat Security Advisory: kernel security update
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.3 Critical · fixed in Red Hat package updates : patch Linux kernel as a priority.
Data as of 29 Oct 2026, 07:55 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 9.3 |
|---|
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in f3e835af6226f1dd12160cbd696081e9b6155de0, c3e33464746166264334641dc850a36eef7e6326, a464d950f31c89565cbaae038cc60db04fe01956 +5
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
Red Hat has released updated kernel packages that fix this vulnerability. Users of Red Hat Enterprise Linux 6 Extended Lifecycle Support should apply the kernel update as described in the Red Hat advisory and reboot their systems to ensure the fix takes effect. Red Hat strongly advises against delaying this update to avoid exposure.
Description
A security update for the Linux kernel in Red Hat Enterprise Linux 6 Extended Lifecycle Support addresses a vulnerability identified as CVE-2026-99999. The issue involves improper validation of the checksum_start value in the IPv4 implementation. Red Hat has released patches to fix this vulnerability and recommends applying the update and rebooting the system to ensure protection. The update is rated as Important by Red Hat Product Security.