VulnerabilityPublished 25 Jan 2026Updated 19 Oct 2026

CVE-2026-23005: Linux kernel · Improper Input Validation

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f577508cc8a0adb8b4ebe9480bba7683b6149930 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

EPSS

0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-06-10.

Patch

Available – fixed in f577508cc8a0adb8b4ebe9480bba7683b6149930, eea6f395ca502c4528314c8112da9b5d65f685eb, b5995c01ba53d84182ecb9492fc4d91cfe8a362d +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 820a6ee944e74e57255ac2e90916ecdaade57b95, < f577508cc8a0adb8b4ebe9480bba7683b6149930	Fixed in f577508cc8a0adb8b4ebe9480bba7683b6149930
LinuxLinux	Affected ≥ 820a6ee944e74e57255ac2e90916ecdaade57b95, < eea6f395ca502c4528314c8112da9b5d65f685eb	Fixed in eea6f395ca502c4528314c8112da9b5d65f685eb
LinuxLinux	Affected ≥ 820a6ee944e74e57255ac2e90916ecdaade57b95, < b5995c01ba53d84182ecb9492fc4d91cfe8a362d	Fixed in b5995c01ba53d84182ecb9492fc4d91cfe8a362d
LinuxLinux	Affected ≥ 820a6ee944e74e57255ac2e90916ecdaade57b95, < b45f721775947a84996deb5c661602254ce25ce6	Fixed in b45f721775947a84996deb5c661602254ce25ce6
LinuxLinux	Affected ≥ 820a6ee944e74e57255ac2e90916ecdaade57b95, < 1e2848bda819af569dfe7ab186223855e092a2cb	Fixed in 1e2848bda819af569dfe7ab186223855e092a2cb
LinuxLinux	Affected =5.17	Fixed in–

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel. Systems running affected versions should apply the official kernel updates containing the fix. No additional mitigation steps are required beyond applying the patch.

Description

A Linux kernel vulnerability in the x86/fpu subsystem was fixed by ensuring that the guest XSAVE state clears XSTATE_BV bits for features disabled via the guest's XFD. Without this fix, loading guest XSAVE state with mismatched XFD and XSTATE_BV bits could cause the kernel to execute XRSTOR with invalid state, leading to a #NM exception and kernel panic. This issue occurs in KVM virtualization environments when guest WRMSR instructions update XFD and userspace sets XSTATE_BV inconsistently. The fix aligns behavior with Intel's architecture specification by clearing XSTATE_BV bits for disabled features, preventing kernel crashes.

CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Server Side Include (SSI) Injection (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Command Line Execution through SQL Injection (opens in a new tab)
Object Relational Mapping Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 15:55 UTC

WeaknessesCWE-20

Technical details

References

Community reviews

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