CVE-2025-71085VulnerabilityPublished 9 Mar 2026Updated 30 Jul 2026

Red Hat Security Advisory: kernel-rt security update

Affects Linux kernelSource GCVE Database

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Mentioned vulnerabilities

CVE-2026-23001

Authoritative record:CVE-2025-71085· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in Red Hat package updates : patch Linux kernel soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in c53aa6a5086f03f19564096ee084a202a8c738c0, bf3709738d8a8cc6fa275773170c5c29511a0b24, 73744ad5696dce0e0f43872aba8de6a83d6ad570 +4

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Jan 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.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < c53aa6a5086f03f19564096ee084a202a8c738c0	Fixed in c53aa6a5086f03f19564096ee084a202a8c738c0
LinuxLinux	Affected ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < bf3709738d8a8cc6fa275773170c5c29511a0b24	Fixed in bf3709738d8a8cc6fa275773170c5c29511a0b24
LinuxLinux	Affected ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 73744ad5696dce0e0f43872aba8de6a83d6ad570	Fixed in 73744ad5696dce0e0f43872aba8de6a83d6ad570
LinuxLinux	Affected ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 86f365897068d09418488165a68b23cb5baa37f2	Fixed in 86f365897068d09418488165a68b23cb5baa37f2
LinuxLinux	Affected ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 58fc7342b529803d3c221101102fe913df7adb83	Fixed in 58fc7342b529803d3c221101102fe913df7adb83
LinuxLinux	Affected ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 6b7522424529556c9cbc15e15e7bd4eeae310910	Fixed in 6b7522424529556c9cbc15e15e7bd4eeae310910

AI-suggested

Red Hat has released updated kernel packages for Red Hat Enterprise Linux 8 that address these vulnerabilities. Users should apply the kernel update as described in the Red Hat advisory (https://access.redhat.com/articles/11258) and reboot affected systems to ensure the fixes take effect.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Security Fix(es): * kernel: ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr() (CVE-2025-71085) * kernel: macvlan: fix possible UAF in macvlan_forward_source() (CVE-2026-23001) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Impact

The vulnerabilities could cause kernel crashes or memory corruption due to a BUG() in IPv6 packet processing and a use-after-free in the macvlan network driver. This may affect system stability and security on affected Red Hat Enterprise Linux 8 systems. No known exploits in the wild have been reported. The overall security impact is rated as moderate by Red Hat.

Summary

The Red Hat security advisory RHSA-2026:3963 addresses two vulnerabilities in the kernel-rt packages for Red Hat Enterprise Linux 8. CVE-2025-71085 is a BUG() triggered in the IPv6 code path within pskb_expand_head() as part of calipso_skbuff_setattr(). CVE-2026-23001 is a potential use-after-free vulnerability in the macvlan driver's macvlan_forward_source() function. Both issues could lead to kernel instability or memory corruption. The advisory provides updated kernel packages that fix these vulnerabilities. The update requires a system reboot to take effect.

CWE-190Integer Overflow or Wraparound (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
Requirements
Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.3 (opens in a new tab)
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
Attack patterns
Forced Integer Overflow (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (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)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Jul 2026, 10:47 UTC

WeaknessesCWE-190, CWE-416

Technical details

References

Community reviews

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