Intel

CVE-2026-53012

Linux kernel (GCP) vulnerabilities

mediumEPSS 0.1%

Description

In the Linux kernel, the following vulnerability has been resolved: nexthop: fix IPv6 route referencing IPv4 nexthop syzbot reported a panic [1] [2]. When an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag of all groups containing this nexthop is not updated. This is because nh_group_v4_update is only called when replacing AF_INET to AF_INET6, but the reverse direction (AF_INET6 to AF_INET) is missed. This allows a stale has_v4=false to bypass fib6_check_nexthop, causing IPv6 routes to be attached to groups that effectively contain only AF_INET members. Subsequent route lookups then call nexthop_fib6_nh() which returns NULL for the AF_INET member, leading to a NULL pointer dereference. Fix by calling nh_group_v4_update whenever the family changes, not just AF_INET to AF_INET6. Reproducer: # AF_INET6 blackhole ip -6 nexthop add id 1 blackhole # group with has_v4=false ip nexthop add id 100 group 1 # replace with AF_INET (no -6), has_v4 stays false ip nexthop replace id 1 blackhole # pass stale has_v4 check ip -6 route add 2001:db8::/64 nhid 100 # panic ping -6 2001:db8::1 [1] https://syzkaller.appspot.com/bug?id=e17283eb2f8dcf3dd9b47fe6f67a95f71faadad0 [2] https://syzkaller.appspot.com/bug?id=8699b6ae54c9f35837d925686208402949e12ef3

Source: UBUNTU_USNSIEMENS_ADVISORYUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNBSIBSI_CSAFUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNUBUNTU_USNMSRCCVELISTV5NVDCVEORG

Metrics

Severity
medium
Priority score
231.31
KEV status
—
Exploit maturity
no public PoC known
XIEM Effective CVSS
5.5
Source: nvd-v3
CVSS v3
5.5
CVSS v4
—
EPSS percentile
3.2 %
Low — this CVE sits in the lower 10% of all CVEs scored today.
EPSS score
0.1 %
Low — model estimates < 1% exploitation likelihood.
Published
2026-09-07 09:05 UTC
CWE
—

Reanalysis & status changes

Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

  1. CVE Modified2026-09-08 09:18 UTC· 416baaa9-dc9f-4396-8d5f-8c081fb06d67
    • Reference: https://git.kernel.org/stable/c/29c95185ba32b621fbc3800fb86e7dc3edf5c2be
    • Reference: https://git.kernel.org/stable/c/613c8f4a501421dd258b07ea614205d4e16ec845
    • Reference: https://git.kernel.org/stable/c/6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8
    • Reference: https://git.kernel.org/stable/c/9c2d6770a5f4545a307eb66979bef7656a34d621
  2. CVE Modified2026-09-08 09:18 UTC· 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
    • Affected: New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/53xxx/CVE-2026-53012.json">CVE-2026-53012</a>
    • Reference: https://cert-portal.siemens.com/productcert/html/ssa-019113.html
  3. New CVE Received2026-06-24 17:17 UTC· 416baaa9-dc9f-4396-8d5f-8c081fb06d67
    • Affected: Linux, Linux
    • Description: In the Linux kernel, the following vulnerability has been resolved: nexthop: fix IPv6 route referencing IPv4 nexthop syzbot reported a panic [1] [2]. When an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag of all groups containing this nexthop is not updated. This is because nh_group_v4_update is only called when replacing AF_INET to AF_INET6, but the reverse direction (AF_INET6 to AF_INET) is missed. This allows a stale has_v4=false to bypass fib6_check_nexthop, causing IPv6 routes to be attached to groups that effectively contain only AF_INET members. Subsequent route lookups then call nexthop_fib6_nh() which returns NULL for the AF_INET member, leading to a NULL pointer dereference. Fix by calling nh_group_v4_update whenever the family changes, not just AF_INET to AF_INET6. Reproducer: # AF_INET6 blackhole ip -6 nexthop add id 1 blackhole # group with has_v4=false ip nexthop add id 100 group 1 # replace with AF_INET (no -6), has_v4 stays false ip nexthop replace id 1 blackhole # pass stale has_v4 check ip -6 route add 2001:db8::/64 nhid 100 # panic ping -6 2001:db8::1 [1] https://syzkaller.appspot.com/bug?id=e17283eb2f8dcf3dd9b47fe6f67a95f71faadad0 [2] https://syzkaller.appspot.com/bug?id=8699b6ae54c9f35837d925686208402949e12ef3
    • Reference: https://git.kernel.org/stable/c/29c95185ba32b621fbc3800fb86e7dc3edf5c2be
    • Reference: https://git.kernel.org/stable/c/613c8f4a501421dd258b07ea614205d4e16ec845

Affected operating systems

  • linux

    redhat / enterprise_linux10.0

  • linux

    redhat / enterprise_linux7.0

  • linux

    redhat / enterprise_linux8.0

  • linux

    redhat / enterprise_linux9.0

  • linux

    ubuntu / linux-aws-6.8jammy

  • linux

    ubuntu / linux-azureresolute

  • linux

    ubuntu / linux-azuretrusty

  • linux

    ubuntu / linux-azurexenial

  • linux

    ubuntu / linux-azure-4.15bionic

  • linux

    ubuntu / linux-azure-5.4bionic

  • linux

    ubuntu / linux-azure-fdenoble

  • linux

    ubuntu / linux-azure-fderesolute

  • linux

    ubuntu / linux-azure-fde-6.8jammy

  • linux

    ubuntu / linux-azure-fipsbionic

  • linux

    ubuntu / linux-azure-fipsfocal

  • linux

    ubuntu / linux-azure-fipsnoble

  • linux

    ubuntu / linux-fipsjammy

  • linux

    ubuntu / linux-gcp-7.0noble

  • linux

    ubuntu / linux-gkejammy

  • linux

    ubuntu / linux-nvidia-tegranoble

  • linux

    ubuntu / linux-raspinoble

  • linux

    ubuntu / linux-raspi-realtimenoble

  • linux

    linux / linux_kernel2.6.12

  • linux

    linux / linux_kernel2.6.15

References & sources

Linked CVEs

Show 1392 more CVEs
IDCVE-2026-53012
Linux kernel (GCP) vulnerabilities — CVE-2026-53012 | NEOSEC Intel