Skip to main content

Linux Kernel EUVDEUVD-2026-59626

| CVE-2026-74561 HIGH
2026-08-15 Linux GHSA-x2q4-hjx7-v4h6
8.8
CVSS 3.1 · Vendor: Linux
Share

Severity by source

Vendor (Linux) PRIMARY
8.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
vuln.today AI
7.8 HIGH

Race condition requires winning a narrow concurrent scheduling window, warranting AC:H over NVD's AC:L; all other metrics align with kernel UAF achieving scope change.

3.1 AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
4.0 AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE
7.0 HIGH
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Red Hat
5.5 MEDIUM
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 12:26 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
8.8 (HIGH)
Patch available
Aug 15, 2026 - 13:04 EUVD
CVE Published
Aug 15, 2026 - 12:28 cve.org
UNKNOWN (no severity yet)
CVE Published
Aug 15, 2026 - 12:28 cve.org
HIGH 8.8

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush

nh_rt_cache_flush() walks nh->f6i_list during an RTNL-serialized nexthop replace without holding nh->lock, racing the unlocked IPv6 route add/delete that mutate the list under nh->lock and free fib6_info entries (nh_rt_cache_flush() is inlined into rtm_new_nexthop()):

BUG: KASAN: slab-use-after-free in nh_rt_cache_flush (net/ipv4/nexthop.c:2243) Read of size 8 at addr ffff888012953e18 by task exploit/146 nh_rt_cache_flush (net/ipv4/nexthop.c:2243) replace_nexthop (net/ipv4/nexthop.c:2610) rtm_new_nexthop (net/ipv4/nexthop.c:3323) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)

Unlike the other f6i_list walks, this one bumps each route's sernum via fib6_update_sernum_upto_root(), which needs tb6_lock; taking nh->lock around it would invert the established tb6_lock -> nh->lock order and deadlock. As the only purpose is to invalidate cached dsts, bump the IPv6 sernum for the whole netns with rt_genid_bump_ipv6() instead, mirroring the rt_cache_flush() already done for IPv4 just above.

AnalysisAI

Use-after-free race condition in the Linux kernel nexthop subsystem (net/ipv4/nexthop.c) allows a local attacker with low-privilege access to trigger slab-use-after-free in kernel memory, potentially achieving full kernel code execution with scope change across the system. The race occurs between nh_rt_cache_flush() walking nh->f6i_list without holding nh->lock and concurrent IPv6 route add/delete operations freeing fib6_info entries under nh->lock - confirmed by an in-kernel KASAN trace naming the task 'exploit/146'. …

Unlock full vulnerability intelligence

  • Risk assessment & exploitation conditions
  • Attack chain visualization
  • Remediation with exact patch versions
  • Threat intelligence from 22 sources
  • Personal watchlist & email alerts

Free forever · No credit card required

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Obtain local unprivileged shell access
Delivery
Create user/network namespace to gain CAP_NET_ADMIN
Exploit
Configure IPv6 nexthop object with associated fib6_info route entries
Execution
Simultaneously trigger nexthop replace (RTM_NEWNEIGHBOUR) and concurrent IPv6 route deletion
Persist
Win race between unlocked f6i_list walk and nh->lock-protected fib6_info free
Impact
Trigger slab-use-after-free for kernel code execution or denial of service

Vulnerability AssessmentAI

Exploitation Exploitation requires a local user account with the ability to perform RTM_NEWNEIGHBOUR nexthop replace netlink operations and concurrent IPv6 route mutations, which in practice requires CAP_NET_ADMIN within a network namespace. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H scores 8.8, reflecting that a low-privileged local attacker can reach the kernel networking subsystem with scope change and full C/I/A impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A local user with a standard unprivileged account creates a user network namespace to gain CAP_NET_ADMIN, configures IPv6 nexthop objects with associated fib6_info route entries, then races two concurrent operations: one thread repeatedly issuing RTM_NEWNEIGHBOUR nexthop replace netlink messages (triggering nh_rt_cache_flush() and its unlocked f6i_list walk) while a second thread rapidly adds and deletes IPv6 routes attached to the same nexthop (freeing fib6_info entries under nh->lock). When the race window is won, nh_rt_cache_flush() reads from a freed fib6_info slab object - the KASAN trace in the CVE description (task named 'exploit/146', read at addr ffff888012953e18) confirms this path was triggered during vulnerability research. …
Remediation Upgrade to a Linux kernel version incorporating the fix: Linux 7.1.8 or Linux 7.2-rc6 for the 7.x upstream series, or Linux 6.16 for the 6.x series, as confirmed by EUVD-2026-59626. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, acquire the vendor-released patch for your Linux kernel version and begin staging the update in your development environment. …

Sign in for detailed remediation steps and compensating controls.

Threat intelligence, references, and detailed analysis are available after sign-in.

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 16.0 Not-Affected

Share

EUVD-2026-59626 vulnerability details – vuln.today

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy